@article{
 title = {Measurement-based time evolution for quantum simulation of fermionic systems},
 type = {article},
 year = {2022},
 pages = {L032013},
 volume = {4},
 websites = {https://link.aps.org/doi/10.1103/PhysRevResearch.4.L032013},
 month = {7},
 day = {25},
 id = {38985ae8-b868-3feb-8b82-6e1f7f56044c},
 created = {2021-10-29T14:35:49.146Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-29T18:17:34.088Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lee2022},
 private_publication = {false},
 abstract = {Quantum simulation using time evolution in phase estimation-based quantum algorithms can yield unbiased solutions of classically intractable models. But long runtimes open such algorithms to decoherence. We show how measurement-based quantum simulation uses effective time evolution via measurement to allow runtime advantages over conventional circuit-based algorithms that use real-time evolution with quantum gates. We construct a hybrid algorithm to find energy eigenvalues in fermionic models using only measurements on graph states. We apply the algorithm to the Kitaev and Hubbard chains. Resource estimates show a runtime advantage if measurements can be performed faster than gates. Our work sets the stage to allow advances in measurement precision to improve quantum simulation.},
 bibtype = {article},
 author = {Lee, Woo-Ram and Qin, Zhangjie and Raussendorf, Robert and Sela, Eran and Scarola, V. W.},
 doi = {10.1103/PhysRevResearch.4.L032013},
 journal = {Physical Review Research},
 number = {3}
}

Quantum simulation using time evolution in phase estimation-based quantum algorithms can yield unbiased solutions of classically intractable models. But long runtimes open such algorithms to decoherence. We show how measurement-based quantum simulation uses effective time evolution via measurement to allow runtime advantages over conventional circuit-based algorithms that use real-time evolution with quantum gates. We construct a hybrid algorithm to find energy eigenvalues in fermionic models using only measurements on graph states. We apply the algorithm to the Kitaev and Hubbard chains. Resource estimates show a runtime advantage if measurements can be performed faster than gates. Our work sets the stage to allow advances in measurement precision to improve quantum simulation.

@article{
 title = {Fractional quantum Hall effect at the filling factor $\nu=5/2$},
 type = {article},
 year = {2022},
 keywords = {Landau level mixing,Majorana fermion,PH-Pfaffian state,Pfaffian state,anti-Pfaffian state,anyons,bulk probes,composite fermion,disorder,edge probes,edge theory,particle hole symmetry,thermal Hall conductance,thermal equilibration,topological order},
 websites = {http://arxiv.org/abs/2208.07908},
 month = {8},
 day = {16},
 id = {0f00002d-81d3-3a70-9383-969ed010448c},
 created = {2022-08-18T00:41:51.272Z},
 accessed = {2022-08-17},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2023-01-02T15:23:01.169Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The fractional quantum Hall (FQH) effect at the filling factor $\nu=5/2$ was discovered in GaAs heterostructures more than 35 years ago. Various topological orders have been proposed as possible candidates to describe this FQH state. Some of them possess non-Abelian anyon excitations, an entirely new type of quasiparticle with fascinating properties. If observed, non-Abelian anyons could offer fundamental building blocks of a topological quantum computer. Nevertheless, the nature of the FQH state at $\nu=5/2$ is still under debate. In this chapter, we provide an overview of the theoretical background, numerical results, and experimental measurements pertaining to this special FQH state. Furthermore, we review some recent developments and their possible interpretations. Possible future directions toward resolving the nature of the $5/2$ state are also discussed.},
 bibtype = {article},
 author = {Ma, Ken K. W. and Peterson, Michael R. and Scarola, V. W. and Yang, Kun},
 journal = {arxiv:2208.07908}
}

The fractional quantum Hall (FQH) effect at the filling factor $\nu=5/2$ was discovered in GaAs heterostructures more than 35 years ago. Various topological orders have been proposed as possible candidates to describe this FQH state. Some of them possess non-Abelian anyon excitations, an entirely new type of quasiparticle with fascinating properties. If observed, non-Abelian anyons could offer fundamental building blocks of a topological quantum computer. Nevertheless, the nature of the FQH state at $\nu=5/2$ is still under debate. In this chapter, we provide an overview of the theoretical background, numerical results, and experimental measurements pertaining to this special FQH state. Furthermore, we review some recent developments and their possible interpretations. Possible future directions toward resolving the nature of the $5/2$ state are also discussed.

@article{
 title = {Stabilizing topological superfluidity of lattice fermions},
 type = {article},
 year = {2021},
 pages = {033322},
 volume = {104},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.104.033322},
 month = {9},
 day = {27},
 id = {982a779f-6f3d-3581-bc9d-ec5dc4912de0},
 created = {2021-06-10T00:42:15.512Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-06-29T20:53:06.451Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Zhang2021},
 private_publication = {false},
 abstract = {Attractive interaction between spinless fermions in a two-dimensional lattice drives the formation of a topological superfluid. But the topological phase is dynamically unstable towards phase separation when the system has a high density of states and large interaction strength. This limits the critical temperature to an experimentally challenging regime where, for example, even ultracold atoms and molecules in optical lattices would struggle to realize the topological superfluid. We propose that the introduction of a weaker longer-range repulsion, in addition to the short-range attraction between lattice fermions, will suppress the phase separation instability. Taking the honeycomb lattice as an example, we show that our proposal significantly enlarges the stable portion of the topological superfluid phase and increases the critical temperature by an order of magnitude. Our work opens a route to enhance the stability of topological superfluids by engineering inter-particle interactions.},
 bibtype = {article},
 author = {Zhang, Junhua and Tewari, Sumanta and Scarola, V W},
 doi = {10.1103/PhysRevA.104.033322},
 journal = {Physical Review A},
 number = {3}
}

Attractive interaction between spinless fermions in a two-dimensional lattice drives the formation of a topological superfluid. But the topological phase is dynamically unstable towards phase separation when the system has a high density of states and large interaction strength. This limits the critical temperature to an experimentally challenging regime where, for example, even ultracold atoms and molecules in optical lattices would struggle to realize the topological superfluid. We propose that the introduction of a weaker longer-range repulsion, in addition to the short-range attraction between lattice fermions, will suppress the phase separation instability. Taking the honeycomb lattice as an example, we show that our proposal significantly enlarges the stable portion of the topological superfluid phase and increases the critical temperature by an order of magnitude. Our work opens a route to enhance the stability of topological superfluids by engineering inter-particle interactions.

@article{
 title = {Quantifying entanglement in cluster states built with error-prone interactions},
 type = {article},
 year = {2021},
 pages = {043118},
 volume = {3},
 websites = {https://link.aps.org/doi/10.1103/PhysRevResearch.3.043118},
 month = {11},
 publisher = {American Physical Society},
 day = {15},
 id = {e7546765-aaae-30f1-9603-aed35749be49},
 created = {2021-11-15T17:15:35.297Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:59.154Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Qin2021},
 private_publication = {false},
 abstract = {Measurements on cluster states can be used to process quantum information. But errors in cluster states naturally accrue as error-prone inter-particle interactions entangle qubits. We consider one-dimensional cluster states built from controlled phase, Ising, and XY interactions with slow two-qubit error in the interaction strength, consistent with error models of interactions found in a variety of qubit architectures. We focus on measurement protocols designed to implement perfect teleportation wherein quantum information moves across a cluster state intact. Deviations from perfect teleportation offer a proxy for entanglement that can be degraded by two-qubit gate errors. We detail an experimentally viable teleportation fidelity that offers a measure of the impact of error on the cluster state as a whole. Our fidelity calculations show that the error has a distinctly different impact depending on the underlying interaction used for the two-qubit entangling gate. In particular, the Ising and XY interactions can allow perfect teleportation through the cluster state even with large errors, but the controlled phase interaction does not. Nonetheless, we find that teleportation through cluster state chains of size $N$ has a maximum two-qubit error for teleportation along a quantum channel that decreases as $N^-1/2$. To allow construction of larger cluster states, we also design lowest-order refocusing pulses for correcting slow errors in the interaction strength. Our work generalizes to higher-dimensional cluster states and sets the stage for experiments to monitor the growth of entanglement in cluster states built from error-prone interactions.},
 bibtype = {article},
 author = {Qin, Zhangjie and Lee, Woo-Ram and DeMarco, Brian and Gadway, Bryce and Kotochigova, Svetlana and Scarola, V. W.},
 doi = {10.1103/PhysRevResearch.3.043118},
 journal = {Physical Review Research},
 number = {4}
}

Measurements on cluster states can be used to process quantum information. But errors in cluster states naturally accrue as error-prone inter-particle interactions entangle qubits. We consider one-dimensional cluster states built from controlled phase, Ising, and XY interactions with slow two-qubit error in the interaction strength, consistent with error models of interactions found in a variety of qubit architectures. We focus on measurement protocols designed to implement perfect teleportation wherein quantum information moves across a cluster state intact. Deviations from perfect teleportation offer a proxy for entanglement that can be degraded by two-qubit gate errors. We detail an experimentally viable teleportation fidelity that offers a measure of the impact of error on the cluster state as a whole. Our fidelity calculations show that the error has a distinctly different impact depending on the underlying interaction used for the two-qubit entangling gate. In particular, the Ising and XY interactions can allow perfect teleportation through the cluster state even with large errors, but the controlled phase interaction does not. Nonetheless, we find that teleportation through cluster state chains of size $N$ has a maximum two-qubit error for teleportation along a quantum channel that decreases as $N^-1/2$. To allow construction of larger cluster states, we also design lowest-order refocusing pulses for correcting slow errors in the interaction strength. Our work generalizes to higher-dimensional cluster states and sets the stage for experiments to monitor the growth of entanglement in cluster states built from error-prone interactions.

@article{
 title = {Two-particle correlation functions in cluster perturbation theory : Hubbard spin susceptibilities},
 type = {article},
 year = {2020},
 pages = {75122},
 volume = {101},
 websites = {https://doi.org/10.1103/PhysRevB.101.075122},
 publisher = {American Physical Society},
 id = {87837ad0-b41a-369a-ade2-bc5b01d06577},
 created = {2020-02-18T20:46:41.377Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-02-18T20:50:22.670Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Raum2020},
 private_publication = {false},
 bibtype = {article},
 author = {Raum, P T and Alvarez, G and Maier, Thomas and Scarola, V W},
 doi = {10.1103/PhysRevB.101.075122},
 journal = {Physical Review B},
 number = {7}
}

@article{
 title = {Nondestructive dispersive imaging of rotationally excited ultracold molecules},
 type = {article},
 year = {2020},
 pages = {20531-20544},
 volume = {22},
 websites = {http://xlink.rsc.org/?DOI=D0CP03419C},
 id = {e0e87260-8216-378e-8e8a-ec77a5bda324},
 created = {2020-06-08T18:06:15.045Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-11-21T14:53:21.517Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Guan2020},
 private_publication = {false},
 abstract = {The setup for polarization-based dispersive imaging of molecules that relies on the intrinsic anistropy of their excited states to generate optical birefringence.},
 bibtype = {article},
 author = {Guan, Qingze and Highman, Michael and Meier, Eric J. and Williams, Garrett R. and Scarola, Vito and DeMarco, Brian and Kotochigova, Svetlana and Gadway, Bryce},
 doi = {10.1039/D0CP03419C},
 journal = {Physical Chemistry Chemical Physics},
 number = {36}
}

The setup for polarization-based dispersive imaging of molecules that relies on the intrinsic anistropy of their excited states to generate optical birefringence.

@article{
 title = {Particle-hole-symmetric model for a paired fractional quantum Hall state in a half-filled Landau level},
 type = {article},
 year = {2019},
 pages = {045126},
 volume = {99},
 websites = {https://link.aps.org/doi/10.1103/PhysRevB.99.045126},
 month = {1},
 publisher = {American Physical Society},
 day = {14},
 id = {c667e545-1d51-37eb-adb0-788cc66dc358},
 created = {2019-01-14T23:21:08.568Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-05-09T22:42:37.586Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Hutzel2019},
 private_publication = {false},
 abstract = {The fractional quantum Hall effect (FQHE) observed at half filling of the second Landau level is believed to be caused by a pairing of composite fermions (CFs) captured by the Moore-Read Pfaffian wave function. The generating Hamiltonian for the Moore-Read Pfaffian is a purely three-body model that breaks particle-hole symmetry and lacks other properties, such as dominate two-body repulsive interactions, expected from a physical model of the FQHE. We use exact diagonalization to study the low energy states of a more physical two-body generator model derived from the three-body model. We find that the two-body model exhibits the essential features expected from the Moore-Read Pfaffian: pairing, non-Abelian anyon excitations, and a neutral fermion mode. The model also satisfies constraints expected for a physical model of the FQHE at half-filling because it is: short range, spatially decaying, particle-hole symmetric, and supports a roton mode with a robust spectral gap in the thermodynamic limit. Hence, this two-body model offers a bridge between artificial three-body generator models for paired states and the physical Coulomb interaction and can be used to further explore properties of non-Abelian physics in the FQHE.},
 bibtype = {article},
 author = {Hutzel, William and McCord, John J. and Raum, P. T. and Stern, Ben and Wang, Hao and Scarola, V. W. and Peterson, Michael R.},
 doi = {10.1103/PhysRevB.99.045126},
 journal = {Physical Review B},
 number = {4}
}

The fractional quantum Hall effect (FQHE) observed at half filling of the second Landau level is believed to be caused by a pairing of composite fermions (CFs) captured by the Moore-Read Pfaffian wave function. The generating Hamiltonian for the Moore-Read Pfaffian is a purely three-body model that breaks particle-hole symmetry and lacks other properties, such as dominate two-body repulsive interactions, expected from a physical model of the FQHE. We use exact diagonalization to study the low energy states of a more physical two-body generator model derived from the three-body model. We find that the two-body model exhibits the essential features expected from the Moore-Read Pfaffian: pairing, non-Abelian anyon excitations, and a neutral fermion mode. The model also satisfies constraints expected for a physical model of the FQHE at half-filling because it is: short range, spatially decaying, particle-hole symmetric, and supports a roton mode with a robust spectral gap in the thermodynamic limit. Hence, this two-body model offers a bridge between artificial three-body generator models for paired states and the physical Coulomb interaction and can be used to further explore properties of non-Abelian physics in the FQHE.

@article{
 title = {Majorana Corner Modes with Solitons in an Attractive Hubbard-Hofstadter Model of Cold Atom Optical Lattices},
 type = {article},
 year = {2019},
 keywords = {doi:10.1103/PhysRevLett.123.060402 url:https://doi},
 pages = {060402},
 volume = {123},
 websites = {https://link.aps.org/doi/10.1103/PhysRevLett.123.060402},
 month = {8},
 publisher = {American Physical Society},
 day = {6},
 id = {7d6de181-df83-37d8-8f1a-d49c686facf0},
 created = {2019-08-22T16:09:46.871Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-02-03T23:45:33.544Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Zeng2019a},
 private_publication = {false},
 abstract = {Higher order topological superconductors hosting Majorana-Kramers pairs (MKPs) as corner modes have recently been proposed in a two-dimensional (2D) quantum spin Hall insulator (QSHI) proximity-coupled to unconventional cuprate or iron-based superconductors. Here, we show that such MKPs can be realized using a conventional s-wave superfluid with a soliton in cold atom systems governed by the Hubbard-Hofstadter model. The MKPs emerge in the presence of interaction at the ``corners'' defined by the intersections of line solitons and the one-dimensional edges of the system. Our scheme is based on the recently realized cold atom Hubbard-Hofstadter lattice and will pave the way for observing Majorana corner modes and possible higher order topological superfluidity with conventional s-wave superfluids/superconductors.},
 bibtype = {article},
 author = {Zeng, Chuanchang and Stanescu, T. D. and Zhang, Chuanwei and Scarola, V. W. and Tewari, Sumanta},
 doi = {10.1103/PhysRevLett.123.060402},
 journal = {Physical Review Letters},
 number = {6}
}

Higher order topological superconductors hosting Majorana-Kramers pairs (MKPs) as corner modes have recently been proposed in a two-dimensional (2D) quantum spin Hall insulator (QSHI) proximity-coupled to unconventional cuprate or iron-based superconductors. Here, we show that such MKPs can be realized using a conventional s-wave superfluid with a soliton in cold atom systems governed by the Hubbard-Hofstadter model. The MKPs emerge in the presence of interaction at the ``corners'' defined by the intersections of line solitons and the one-dimensional edges of the system. Our scheme is based on the recently realized cold atom Hubbard-Hofstadter lattice and will pave the way for observing Majorana corner modes and possible higher order topological superfluidity with conventional s-wave superfluids/superconductors.

@article{
 title = {Flux-driven quantum spin liquids in kagome optical lattices},
 type = {article},
 year = {2019},
 keywords = {doi:10.1103/PhysRevA.100. url:https://doi.or},
 pages = {053614},
 volume = {100},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.100.053614},
 month = {11},
 publisher = {American Physical Society},
 day = {14},
 id = {36da6e0c-8b09-37aa-8548-2beaf214aed8},
 created = {2019-11-14T21:30:06.072Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-02-03T23:45:33.555Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Hui2019a},
 private_publication = {false},
 abstract = {Quantum spin liquids (QSLs) define an exotic class of quantum ground states where spins are disordered down to zero temperature and are characterized by macroscopic entanglement and fractionalized excitations. We propose a route to QSLs in kagome optical lattices using applied flux. An optical flux lattice can be applied to induce a uniform flux and chiral three-spin interactions that drive the formation of a gapped chiral spin liquid. A different approach based on recent experiments using laser assisted tunneling and lattice tilt implements a staggered flux pattern which can drive a gapless spin liquid with symmetry protected nodal lines. Our proposal therefore establishes kagome optical lattices with effective flux as a powerful platform for exploration of QSLs.},
 bibtype = {article},
 author = {Hui, Hoi-Yin and Chen, Mengsu and Tewari, Sumanta and Scarola, V. W.},
 doi = {10.1103/PhysRevA.100.053614},
 journal = {Physical Review A},
 number = {5}
}

Quantum spin liquids (QSLs) define an exotic class of quantum ground states where spins are disordered down to zero temperature and are characterized by macroscopic entanglement and fractionalized excitations. We propose a route to QSLs in kagome optical lattices using applied flux. An optical flux lattice can be applied to induce a uniform flux and chiral three-spin interactions that drive the formation of a gapped chiral spin liquid. A different approach based on recent experiments using laser assisted tunneling and lattice tilt implements a staggered flux pattern which can drive a gapless spin liquid with symmetry protected nodal lines. Our proposal therefore establishes kagome optical lattices with effective flux as a powerful platform for exploration of QSLs.

@article{
 title = {Quantum anomalous Hall state from spatially decaying interactions on the decorated honeycomb lattice},
 type = {article},
 year = {2018},
 keywords = {cond-mat.mes-hall,cond-mat.str-el},
 pages = {035114},
 volume = {97},
 websites = {https://link.aps.org/doi/10.1103/PhysRevB.97.035114},
 month = {1},
 day = {9},
 id = {84515ceb-8790-390a-a735-c71b82eee0e2},
 created = {2017-12-12T20:22:23.471Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-05-29T22:28:50.008Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Chen2018},
 source_type = {JOUR},
 notes = {Owner: scarola<br/>Added to JabRef: 2017.06.16},
 private_publication = {false},
 abstract = {Topological phases typically encode topology at the level of the single particle band structure. But a remarkable new class of models shows that quantum anomalous Hall effects can be driven exclusively by interactions, while the parent non-interacting band structure is topologically trivial. Unfortunately, these models have so far relied on interactions that do not spatially decay and are therefore unphysical. We study a model of spinless fermions on a decorated honeycomb lattice. Using complementary methods, mean-field theory and exact diagonalization, we find a robust quantum anomalous Hall phase arising from spatially decaying interactions. Our finding paves the way for observing the quantum anomalous Hall effect driven entirely by interactions.},
 bibtype = {article},
 author = {Chen, Mengsu and Hui, Hoi-Yin and Tewari, Sumanta and Scarola, V W},
 doi = {10.1103/PhysRevB.97.035114},
 journal = {Physical Review B},
 number = {3}
}

Topological phases typically encode topology at the level of the single particle band structure. But a remarkable new class of models shows that quantum anomalous Hall effects can be driven exclusively by interactions, while the parent non-interacting band structure is topologically trivial. Unfortunately, these models have so far relied on interactions that do not spatially decay and are therefore unphysical. We study a model of spinless fermions on a decorated honeycomb lattice. Using complementary methods, mean-field theory and exact diagonalization, we find a robust quantum anomalous Hall phase arising from spatially decaying interactions. Our finding paves the way for observing the quantum anomalous Hall effect driven entirely by interactions.

@article{
 title = {Chiral topological phases in optical lattices without synthetic fields},
 type = {article},
 year = {2018},
 pages = {023609},
 volume = {98},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.98.023609},
 month = {8},
 day = {8},
 id = {ae1753f9-63cb-3476-b5a2-fd4e7344e507},
 created = {2018-08-08T19:46:32.443Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2018-10-18T01:52:20.215Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Hui2018},
 private_publication = {false},
 bibtype = {article},
 author = {Hui, Hoi-Yin and Chen, Mengsu and Tewari, Sumanta and Scarola, V. W.},
 doi = {10.1103/PhysRevA.98.023609},
 journal = {Physical Review A},
 number = {2}
}

@article{
 title = {Correlated spin-flip tunneling in a Fermi lattice gas},
 type = {article},
 year = {2018},
 pages = {023623},
 volume = {98},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.98.023623},
 month = {8},
 publisher = {American Physical Society},
 day = {20},
 id = {7398438a-9e78-339e-9bde-85d42e9332ff},
 created = {2018-09-11T15:45:50.334Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2021-05-18T18:59:21.505Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Xu2017a},
 private_publication = {false},
 abstract = {We report the realization of correlated, density-dependent tunneling for fermionic 40K atoms trapped in an optical lattice. By appropriately tuning the frequency difference between a pair of Raman beams applied to a spin-polarized gas, simultaneous spin transitions and tunneling events are induced that depend on the relative occupations of neighboring lattice sites. Correlated spin-flip tunneling is spectroscopically resolved using gases prepared in opposite spin states, and the inferred Hubbard interaction energy is compared with a tight-binding prediction. We show that the laser-induced correlated tunneling process generates doublons via loss induced by light-assisted collisions. Furthermore, by controllably introducing vacancies to a spin-polarized gas, we demonstrate that correlated tunneling is suppressed when neighboring lattice sites are unoccupied.},
 bibtype = {article},
 author = {Xu, Wenchao and Morong, William and Hui, Hoi-Yin and Scarola, Vito W. and DeMarco, Brian},
 doi = {10.1103/PhysRevA.98.023623},
 journal = {Physical Review A},
 number = {2}
}

We report the realization of correlated, density-dependent tunneling for fermionic 40K atoms trapped in an optical lattice. By appropriately tuning the frequency difference between a pair of Raman beams applied to a spin-polarized gas, simultaneous spin transitions and tunneling events are induced that depend on the relative occupations of neighboring lattice sites. Correlated spin-flip tunneling is spectroscopically resolved using gases prepared in opposite spin states, and the inferred Hubbard interaction energy is compared with a tight-binding prediction. We show that the laser-induced correlated tunneling process generates doublons via loss induced by light-assisted collisions. Furthermore, by controllably introducing vacancies to a spin-polarized gas, we demonstrate that correlated tunneling is suppressed when neighboring lattice sites are unoccupied.

@article{
 title = {Validating quantum-classical programming models with tensor network simulations},
 type = {article},
 year = {2018},
 pages = {e0206704},
 volume = {13},
 websites = {http://dx.plos.org/10.1371/journal.pone.0206704},
 month = {12},
 day = {10},
 id = {acf47e1c-d9b1-37ca-9d23-b52322998288},
 created = {2019-01-26T18:26:02.530Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-07-05T02:11:36.481Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {McCaskey2018},
 private_publication = {false},
 bibtype = {article},
 author = {McCaskey, Alexander and Dumitrescu, Eugene and Chen, Mengsu and Lyakh, Dmitry and Humble, Travis},
 editor = {Chancellor, Nicholas},
 doi = {10.1371/journal.pone.0206704},
 journal = {PLOS ONE},
 number = {12}
}

@article{
 title = {A language and hardware independent approach to quantum–classical computing},
 type = {article},
 year = {2018},
 keywords = {Quantum computing,Quantum software},
 pages = {245-254},
 volume = {7},
 websites = {https://doi.org/10.1016/j.softx.2018.07.007},
 month = {1},
 publisher = {Elsevier B.V.},
 id = {67190312-7562-3f6a-99f8-08213772a86d},
 created = {2019-01-26T18:28:28.037Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-01-28T18:14:45.548Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {McCaskey2018a},
 private_publication = {false},
 abstract = {Heterogeneous high-performance computing (HPC) systems offer novel architectures which accelerate specific workloads through judicious use of specialized coprocessors. A promising architectural approach for future scientific computations is provided by heterogeneous HPC systems integrating quantum processing units (QPUs). To this end, we present XACC (eX treme-scale ACC elerator) — a programming model and software framework that enables quantum acceleration within standard or HPC software workflows. XACC follows a coprocessor machine model that is independent of the underlying quantum computing hardware, thereby enabling quantum programs to be defined and executed on a variety of QPUs types through a unified application programming interface. Moreover, XACC defines a polymorphic low-level intermediate representation, and an extensible compiler frontend that enables language independent quantum programming, thus promoting integration and interoperability across the quantum programming landscape. In this work we define the software architecture enabling our hardware and language independent approach, and demonstrate its usefulness across a range of quantum computing models through illustrative examples involving the compilation and execution of gate and annealing-based quantum programs.},
 bibtype = {article},
 author = {McCaskey, A.J. and Dumitrescu, E.F. and Liakh, D. and Chen, M. and Feng, W. and Humble, T.S.},
 doi = {10.1016/j.softx.2018.07.007},
 journal = {SoftwareX}
}

Heterogeneous high-performance computing (HPC) systems offer novel architectures which accelerate specific workloads through judicious use of specialized coprocessors. A promising architectural approach for future scientific computations is provided by heterogeneous HPC systems integrating quantum processing units (QPUs). To this end, we present XACC (eX treme-scale ACC elerator) — a programming model and software framework that enables quantum acceleration within standard or HPC software workflows. XACC follows a coprocessor machine model that is independent of the underlying quantum computing hardware, thereby enabling quantum programs to be defined and executed on a variety of QPUs types through a unified application programming interface. Moreover, XACC defines a polymorphic low-level intermediate representation, and an extensible compiler frontend that enables language independent quantum programming, thus promoting integration and interoperability across the quantum programming landscape. In this work we define the software architecture enabling our hardware and language independent approach, and demonstrate its usefulness across a range of quantum computing models through illustrative examples involving the compilation and execution of gate and annealing-based quantum programs.

@article{
 title = {Thermometry for Laughlin States of Ultracold Atoms},
 type = {article},
 year = {2017},
 pages = {115302},
 volume = {118},
 websites = {https://link.aps.org/doi/10.1103/PhysRevLett.118.115302},
 month = {3},
 id = {efca33c1-fcb3-3884-9c1a-827007d9aa2b},
 created = {2017-12-12T20:22:21.607Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.321Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Raum2017},
 source_type = {JOUR},
 folder_uuids = {4dea6cad-aea6-4b8d-8508-752e5cfc5357},
 private_publication = {false},
 abstract = {Cooling atomic gases into strongly correlated quantum phases requires estimates of the entropy to perform thermometry and establish viability. We construct an ansatz partition function for models of Laughlin states of atomic gases by combining high temperature series expansions with exact diagonalization. Using the ansatz we find that entropies required to observe Laughlin correlations with bosonic gases are within reach of current cooling capabilities.},
 bibtype = {article},
 author = {Raum, P. T. and Scarola, V. W.},
 doi = {10.1103/PhysRevLett.118.115302},
 journal = {Physical Review Letters},
 number = {11}
}

Cooling atomic gases into strongly correlated quantum phases requires estimates of the entropy to perform thermometry and establish viability. We construct an ansatz partition function for models of Laughlin states of atomic gases by combining high temperature series expansions with exact diagonalization. Using the ansatz we find that entropies required to observe Laughlin correlations with bosonic gases are within reach of current cooling capabilities.

@article{
 title = {Equilibration Dynamics of Strongly Interacting Bosons in 2D Lattices with Disorder},
 type = {article},
 year = {2017},
 pages = {073002},
 volume = {119},
 websites = {https://link.aps.org/doi/10.1103/PhysRevLett.119.073002},
 month = {8},
 day = {14},
 id = {9101c64a-de95-3662-b731-13f0ad53b1f7},
 created = {2017-12-12T20:22:21.725Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-04-24T20:30:18.037Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Yan2017a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Motivated by recent optical lattice experiments [Choi et al., arXiv:1604.04178], we study the dynamics of strongly interacting bosons in the presence of disorder in two dimensions. We show that Gutzwiller mean-field theory (GMFT) captures the main experimental observations, which are a result of the competition between disorder and interactions. Our findings highlight the difficulty in distinguishing glassy dynamics, which can be captured by GMFT, and many-body localization, which cannot be captured by GMFT, and indicate the need for further experimental studies of this system.},
 bibtype = {article},
 author = {Yan, Mi and Hui, Hoi-Yin and Rigol, Marcos and Scarola, V. W.},
 doi = {10.1103/PhysRevLett.119.073002},
 journal = {Physical Review Letters},
 number = {7}
}

Motivated by recent optical lattice experiments [Choi et al., arXiv:1604.04178], we study the dynamics of strongly interacting bosons in the presence of disorder in two dimensions. We show that Gutzwiller mean-field theory (GMFT) captures the main experimental observations, which are a result of the competition between disorder and interactions. Our findings highlight the difficulty in distinguishing glassy dynamics, which can be captured by GMFT, and many-body localization, which cannot be captured by GMFT, and indicate the need for further experimental studies of this system.

@article{
 title = {Disordered Supersolids in the Extended Bose-Hubbard Model},
 type = {article},
 year = {2017},
 keywords = {Condensed Matter - Other Condensed Matter,Condensed Matter - Quantum Gases},
 pages = {12752},
 volume = {7},
 websites = {https://www.nature.com/articles/s41598-017-13040-9},
 month = {12},
 day = {6},
 id = {e7346f5b-f58e-3933-afe4-8203224f2507},
 created = {2017-12-12T20:22:21.984Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:01.064Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lin2017},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We theoretically study the stability of lattice supersolid states\nin the extended Bose-Hubbard model with bounded spatial disorder.\nWe construct a disorder mean-field theory and compare with quantum\nMonte Carlo calculations. The supersolid survives weak disorder on\nthe simple cubic lattice. We also find that increasing disorder strength\ncan transform a lattice solid into a supersolid as it tends to percolate\nthrough the disorder landscape.},
 bibtype = {article},
 author = {Lin, Fei and Maier, T. A. and Scarola, V. W.},
 doi = {10.1038/s41598-017-13040-9},
 journal = {Scientific Reports},
 number = {1}
}

We theoretically study the stability of lattice supersolid states\nin the extended Bose-Hubbard model with bounded spatial disorder.\nWe construct a disorder mean-field theory and compare with quantum\nMonte Carlo calculations. The supersolid survives weak disorder on\nthe simple cubic lattice. We also find that increasing disorder strength\ncan transform a lattice solid into a supersolid as it tends to percolate\nthrough the disorder landscape.

@article{
 title = {Superfluidity in the absence of kinetics in spin-orbit-coupled optical lattices},
 type = {article},
 year = {2017},
 pages = {33603},
 volume = {95},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.95.033603},
 month = {3},
 id = {f6daabb3-8fcc-3093-8bb5-b25f04fb62c2},
 created = {2017-12-12T20:22:23.516Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2021-02-25T17:45:33.957Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Hui2017},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {At low temperatures bosons typically condense to minimize their single-particle kinetic energy while interactions stabilize superfluidity. Optical lattices with artificial spin-orbit coupling challenge this paradigm because here kinetic energy can be quenched in an extreme regime where the single-particle band flattens. To probe the fate of superfluidity in the absence of kinetics we construct and numerically solve interaction-only tight-binding models in flat bands. We find that novel superfluid states arise entirely from interactions operating in quenched kinetic energy bands, thus revealing a distinct and unexpected condensation mechanism. Our results have important implications for the identification of quantum condensed phases of ultracold bosons beyond conventional paradigms.},
 bibtype = {article},
 author = {Hui, Hoi Yin and Zhang, Yongping and Zhang, Chuanwei and Scarola, V. W.},
 doi = {10.1103/PhysRevA.95.033603},
 journal = {Physical Review A},
 number = {3}
}

At low temperatures bosons typically condense to minimize their single-particle kinetic energy while interactions stabilize superfluidity. Optical lattices with artificial spin-orbit coupling challenge this paradigm because here kinetic energy can be quenched in an extreme regime where the single-particle band flattens. To probe the fate of superfluidity in the absence of kinetics we construct and numerically solve interaction-only tight-binding models in flat bands. We find that novel superfluid states arise entirely from interactions operating in quenched kinetic energy bands, thus revealing a distinct and unexpected condensation mechanism. Our results have important implications for the identification of quantum condensed phases of ultracold bosons beyond conventional paradigms.

@article{
 title = {Dynamics of disordered states in the Bose-Hubbard model with confinement},
 type = {article},
 year = {2017},
 pages = {053624},
 volume = {95},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.95.053624},
 month = {5},
 day = {22},
 id = {116fceab-2847-3db2-a0a7-d8b1c3684231},
 created = {2017-12-12T20:22:24.496Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-04-24T20:30:18.033Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Yan2017b},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Observations of center of mass dynamics offer a straightforward method to identify strongly interacting quantum phases of atoms placed in optical lattices. We theoretically study the dynamics of states derived from the disordered Bose-Hubbard model in a trapping potential. We find that the edge states in the trap allow center of mass motion even with insulating states in the center. We identify short and long-time scale mechanisms for edge state transport in insulating phases. We also argue that the center of mass velocity can aid in identifying a Bose-glass phase. Our zero temperature results offer important insights into mechanisms of transport of atoms in trapped optical lattices while putting bounds on center of mass dynamics expected at non-zero temperature.},
 bibtype = {article},
 author = {Yan, Mi and Hui, Hoi-Yin and Scarola, V. W.},
 doi = {10.1103/PhysRevA.95.053624},
 journal = {Physical Review A},
 number = {5}
}

Observations of center of mass dynamics offer a straightforward method to identify strongly interacting quantum phases of atoms placed in optical lattices. We theoretically study the dynamics of states derived from the disordered Bose-Hubbard model in a trapping potential. We find that the edge states in the trap allow center of mass motion even with insulating states in the center. We identify short and long-time scale mechanisms for edge state transport in insulating phases. We also argue that the center of mass velocity can aid in identifying a Bose-glass phase. Our zero temperature results offer important insights into mechanisms of transport of atoms in trapped optical lattices while putting bounds on center of mass dynamics expected at non-zero temperature.

@article{
 title = {Spin-orbit-driven transitions between Mott insulators and finite-momentum superfluids of bosons in optical lattices},
 type = {article},
 year = {2017},
 pages = {053619},
 volume = {96},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.96.053619},
 month = {11},
 day = {13},
 id = {5ec8ed2b-5dad-3a68-bd29-c1d0820cdf44},
 created = {2017-12-12T20:22:25.236Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-01-28T18:14:45.711Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Yan2017},
 source_type = {JOUR},
 notes = {Owner: scarola<br/>Added to JabRef: 2017.06.15<br/><br/><br/>Owner: scarola<br/>Added to JabRef: 2017.06.15},
 private_publication = {false},
 abstract = {We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.},
 bibtype = {article},
 author = {Yan, Mi and Qian, Yinyin and Hui, Hoi-Yin and Gong, Ming and Zhang, Chuanwei and Scarola, V. W.},
 doi = {10.1103/PhysRevA.96.053619},
 journal = {Physical Review A},
 number = {5}
}

We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.

@article{
 title = {Stability of emergent kinetics in optical lattices with artificial spin-orbit coupling},
 type = {article},
 year = {2016},
 pages = {43601},
 volume = {94},
 websites = {http://link.aps.org/doi/10.1103/PhysRevA.94.043601},
 month = {10},
 id = {19bcb1ed-0677-30d4-9eda-8ee045de4f4b},
 created = {2017-12-12T20:22:24.728Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2021-02-25T17:45:33.934Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Chen2016},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Artificial spin-orbit coupling in optical lattices can be engineered to tune band structure into extreme regimes where the single-particle band flattens leaving only inter-particle interactions to define many-body states of matter. Lin et al. [Phys. Rev. Lett 112, 110404 (2014)] showed that under such conditions interactions lead to a Wigner crystal of fermionic atoms under approximate conditions: no bandwidth or band mixing. The excitations were shown to possess emergent kinetics with fractionalized charge derived entirely from interactions. In this work we use numerical exact diagonalization to study a more realistic model with non-zero bandwidth and band mixing. We map out the stability phase diagram of the Wigner crystal. We find that emergent properties of the Wigner crystal excitations remain stable for realistic experimental parameters. Our results validate the approximations made by Lin et al. and define parameter regimes where strong interaction effects generate emergent kinetics in optical lattices.},
 bibtype = {article},
 author = {Chen, Mengsu and Scarola, V. W.},
 doi = {10.1103/PhysRevA.94.043601},
 journal = {Physical Review A},
 number = {4}
}

Artificial spin-orbit coupling in optical lattices can be engineered to tune band structure into extreme regimes where the single-particle band flattens leaving only inter-particle interactions to define many-body states of matter. Lin et al. [Phys. Rev. Lett 112, 110404 (2014)] showed that under such conditions interactions lead to a Wigner crystal of fermionic atoms under approximate conditions: no bandwidth or band mixing. The excitations were shown to possess emergent kinetics with fractionalized charge derived entirely from interactions. In this work we use numerical exact diagonalization to study a more realistic model with non-zero bandwidth and band mixing. We map out the stability phase diagram of the Wigner crystal. We find that emergent properties of the Wigner crystal excitations remain stable for realistic experimental parameters. Our results validate the approximations made by Lin et al. and define parameter regimes where strong interaction effects generate emergent kinetics in optical lattices.

@article{
 title = {Fast and efficient stochastic optimization for analytic continuation},
 type = {article},
 year = {2016},
 pages = {125149},
 volume = {94},
 websites = {https://link.aps.org/doi/10.1103/PhysRevB.94.125149},
 month = {9},
 day = {28},
 id = {cff74692-5142-35e9-90df-1b8fef645639},
 created = {2017-12-12T20:22:26.535Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-08-13T22:00:05.381Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Bao2016},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {The analytic continuation of imaginary-time quantum Monte Carlo data to extract real-frequency spectra remains a key problem in connecting theory with experiment. Here we present a fast and efficient stochastic optimization method (FESOM) as a more accessible variant of the stochastic optimization method introduced by Mishchenko et al. [Phys. Rev. B 62, 6317 (2000)], and we benchmark the resulting spectra with those obtained by the standard maximum entropy method for three representative test cases, including data taken from studies of the two-dimensional Hubbard model. We generally find that our FESOM approach yields spectra similar to the maximum entropy results. In particular, while the maximum entropy method yields superior results when the quality of the data is strong, we find that FESOM is able to resolve fine structure with more detail when the quality of the data is poor. In addition, because of its stochastic nature, the method provides detailed information on the frequency-dependent uncertainty of the resulting spectra, while the maximum entropy method does so only for the spectral weight integrated over a finite frequency region. We therefore believe that this variant of the stochastic optimization approach provides a viable alternative to the routinely used maximum entropy method, especially for data of poor quality.},
 bibtype = {article},
 author = {Bao, F. and Tang, Y. and Summers, M. and Zhang, G. and Webster, C. and Scarola, V. and Maier, T. A.},
 doi = {10.1103/PhysRevB.94.125149},
 journal = {Physical Review B},
 number = {12}
}

The analytic continuation of imaginary-time quantum Monte Carlo data to extract real-frequency spectra remains a key problem in connecting theory with experiment. Here we present a fast and efficient stochastic optimization method (FESOM) as a more accessible variant of the stochastic optimization method introduced by Mishchenko et al. [Phys. Rev. B 62, 6317 (2000)], and we benchmark the resulting spectra with those obtained by the standard maximum entropy method for three representative test cases, including data taken from studies of the two-dimensional Hubbard model. We generally find that our FESOM approach yields spectra similar to the maximum entropy results. In particular, while the maximum entropy method yields superior results when the quality of the data is strong, we find that FESOM is able to resolve fine structure with more detail when the quality of the data is poor. In addition, because of its stochastic nature, the method provides detailed information on the frequency-dependent uncertainty of the resulting spectra, while the maximum entropy method does so only for the spectral weight integrated over a finite frequency region. We therefore believe that this variant of the stochastic optimization approach provides a viable alternative to the routinely used maximum entropy method, especially for data of poor quality.

@article{
 title = {Reordering fractional Chern insulators into stripes of fractional charges with long-range interactions},
 type = {article},
 year = {2015},
 volume = {92},
 websites = {https://doi.org/10.1103/PhysRevB.92.035138},
 id = {47a15e9f-f247-3a6d-9314-b2c18d3744e7},
 created = {2017-12-12T20:22:25.700Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.256Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Chen2015a},
 private_publication = {false},
 abstract = {© 2015 American Physical Society. Long-range interactions drive some of the rich phenomenology of quasiparticle collective states in the fractional quantum Hall regime. We test for analogs in models of fractional Chern insulators (FCIs) derived from a screened Coulomb interaction. We find that the uniform FCI liquid is surprisingly robust to long-range interactions but gives way to a unidirectional charge-density wave of fractionally charged quasiparticles with increased screening length. Our results show that FCIs offer a robust and important platform for studying quasiparticle collective states.},
 bibtype = {article},
 author = {Chen, Mengsu and Scarola, V. W.},
 doi = {10.1103/PhysRevB.92.035138},
 journal = {Physical Review B},
 number = {3}
}

© 2015 American Physical Society. Long-range interactions drive some of the rich phenomenology of quasiparticle collective states in the fractional quantum Hall regime. We test for analogs in models of fractional Chern insulators (FCIs) derived from a screened Coulomb interaction. We find that the uniform FCI liquid is surprisingly robust to long-range interactions but gives way to a unidirectional charge-density wave of fractionally charged quasiparticles with increased screening length. Our results show that FCIs offer a robust and important platform for studying quasiparticle collective states.

@article{
 title = {Dynamics of Hubbard-band quasiparticles in disordered optical lattices},
 type = {article},
 year = {2015},
 pages = {053628},
 volume = {92},
 websites = {http://dx.doi.org/10.1103/PhysRevA.92.053628},
 month = {11},
 day = {30},
 id = {18ab7303-9ef7-3554-9176-fac0a3fc2056},
 created = {2017-12-12T20:22:26.534Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.735Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2015},
 source_type = {JOUR},
 notes = {Owner: scarola<br/>Added to JabRef: 2015.12.21},
 private_publication = {false},
 abstract = {Quantum degenerate gases trapped in optical lattices are ideal testbeds for fundamental physics because these systems are tunable, well characterized, and isolated from the environment. Controlled disorder can be introduced to explore suppression of quantum diffusion in the absence of conventional dephasing mechanisms such as phonons, which are unavoidable in experiments on electronic solids. Recent experiments use transport of degenerate Fermi gases in optical lattices (Kondov et al. Phys. Rev. Lett. 114, 083002 (2015)) to probe a particularly extreme regime of strong interaction in what can be modeled as an Anderson-Hubbard model. These experiments find evidence for an intriguing insulating phase where quantum diffusion is completely suppressed by strong disorder. Quantitative interpretation of these experiments remains an open problem that requires inclusion of non-zero entropy, strong interaction, and trapping. We argue that the suppression of transport can be thought of as localization of Hubbard-band quasiparticles. We construct a theory of transport of Hubbard-band quasiparticles tailored to trapped optical lattice experiments. We compare the theory directly with center-of-mass transport experiments of Kondov et al. with no fitting parameters. The close agreement between theory and experiments shows that the suppression of transport is only partly due to finite entropy effects. We argue that the complete suppression of transport is consistent with Anderson localization of Hubbard-band quasiparticles. The combination of our theoretical framework and optical lattice experiments offers an important platform for studying localization in isolated many-body quantum systems.},
 bibtype = {article},
 author = {Scarola, V. W. and DeMarco, B.},
 doi = {10.1103/PhysRevA.92.053628},
 journal = {Physical Review A},
 number = {5}
}

Quantum degenerate gases trapped in optical lattices are ideal testbeds for fundamental physics because these systems are tunable, well characterized, and isolated from the environment. Controlled disorder can be introduced to explore suppression of quantum diffusion in the absence of conventional dephasing mechanisms such as phonons, which are unavoidable in experiments on electronic solids. Recent experiments use transport of degenerate Fermi gases in optical lattices (Kondov et al. Phys. Rev. Lett. 114, 083002 (2015)) to probe a particularly extreme regime of strong interaction in what can be modeled as an Anderson-Hubbard model. These experiments find evidence for an intriguing insulating phase where quantum diffusion is completely suppressed by strong disorder. Quantitative interpretation of these experiments remains an open problem that requires inclusion of non-zero entropy, strong interaction, and trapping. We argue that the suppression of transport can be thought of as localization of Hubbard-band quasiparticles. We construct a theory of transport of Hubbard-band quasiparticles tailored to trapped optical lattice experiments. We compare the theory directly with center-of-mass transport experiments of Kondov et al. with no fitting parameters. The close agreement between theory and experiments shows that the suppression of transport is only partly due to finite entropy effects. We argue that the complete suppression of transport is consistent with Anderson localization of Hubbard-band quasiparticles. The combination of our theoretical framework and optical lattice experiments offers an important platform for studying localization in isolated many-body quantum systems.

@article{
 title = {Dzyaloshinskii-Moriya Interaction and Spiral Order in Spin-orbit Coupled Optical Lattices},
 type = {article},
 year = {2015},
 pages = {10050},
 volume = {5},
 websites = {http://www.nature.com/articles/srep10050},
 month = {9},
 day = {27},
 id = {01bbe04d-90a3-34ce-aa55-2d0f9339d210},
 created = {2017-12-22T05:13:57.859Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2018-07-25T21:22:58.316Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Gong2015},
 private_publication = {false},
 abstract = {We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.},
 bibtype = {article},
 author = {Gong, Ming and Qian, Yinyin and Yan, Mi and Scarola, V. W. and Zhang, Chuanwei},
 doi = {10.1038/srep10050},
 journal = {Scientific Reports},
 number = {1}
}

We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.

@article{
 title = {Phase diagram of the v = 5/2 fractional quantum Hall effect: Effects of Landau-level mixing and nonzero width},
 type = {article},
 year = {2015},
 pages = {021004},
 volume = {5},
 websites = {http://dx.doi.org/10.1103/PhysRevX.5.021004},
 month = {4},
 day = {2},
 id = {6bff99a6-0f5b-37c6-8b35-a36d30a08a65},
 created = {2020-06-19T15:33:17.579Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2021-05-06T16:13:20.245Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Pakrouski2015},
 source_type = {JOUR},
 notes = {<b>From Duplicate 1 (<i>Phase diagram of the v = 5/2 fractional quantum hall effect: Effects of Landau-level mixing and nonzero width</i> - Pakrouski, Kiryl; Peterson, Michael R.; Jolicoeur, Thierry; Scarola, Vito W.; Nayak, Chetan; Troyer, Matthias)<br/></b><br/>Owner: scarola<br/>Added to JabRef: 2015.09.08},
 private_publication = {false},
 abstract = {Interesting non-Abelian states, e.g., the Moore-Read Pfaffian and the anti-Pfaffian, offer candidate descriptions of the v = 5/2 fractional quantum Hall state. But, the significant controversy surrounding the nature of the v = 5/2 state has been hampered by the fact that the competition between these and other states is affected by small parameter changes. To study the phase diagram of the v = 5/2 state, we numerically diagonalize a comprehensive effective Hamiltonian describing the fractional quantum Hall effect of electrons under realistic conditions in GaAs semiconductors. The effective Hamiltonian takes Landau-level mixing into account to lowest order perturbatively in ?, the ratio of the Coulomb energy scale to the cyclotron gap. We also incorporate the nonzero width w of the quantum-well and subband mixing. We find the ground state in both the torus and spherical geometries as a function of ? and w. To sort out the nontrivial competition between candidate ground states, we analyze the following four criteria: its overlap with trial wave functions, the magnitude of energy gaps, the sign of the expectation value of an order parameter for particle-hole symmetry breaking, and the entanglement spectrum. We conclude that the ground state is in the universality class of the Moore-Read Pfaffian state, rather than the anti-Pfaffian, for ? < ?c(w), where ?c(w) is a w-dependent critical value 0.6 ? ?c(w) ? 1. We observe that both Landau-level mixing and nonzero width suppress the excitation gap, but Landau-level mixing has a larger effect in this regard. Our findings have important implications for the identification of non-Abelian fractional quantum Hall states.},
 bibtype = {article},
 author = {Pakrouski, Kiryl and Peterson, M.R. Michael R. and Jolicoeur, Thierry and Scarola, Vito W. and Nayak, Chetan and Troyer, Matthias},
 doi = {10.1103/PhysRevX.5.021004},
 journal = {Physical Review X},
 number = {2}
}

Interesting non-Abelian states, e.g., the Moore-Read Pfaffian and the anti-Pfaffian, offer candidate descriptions of the v = 5/2 fractional quantum Hall state. But, the significant controversy surrounding the nature of the v = 5/2 state has been hampered by the fact that the competition between these and other states is affected by small parameter changes. To study the phase diagram of the v = 5/2 state, we numerically diagonalize a comprehensive effective Hamiltonian describing the fractional quantum Hall effect of electrons under realistic conditions in GaAs semiconductors. The effective Hamiltonian takes Landau-level mixing into account to lowest order perturbatively in ?, the ratio of the Coulomb energy scale to the cyclotron gap. We also incorporate the nonzero width w of the quantum-well and subband mixing. We find the ground state in both the torus and spherical geometries as a function of ? and w. To sort out the nontrivial competition between candidate ground states, we analyze the following four criteria: its overlap with trial wave functions, the magnitude of energy gaps, the sign of the expectation value of an order parameter for particle-hole symmetry breaking, and the entanglement spectrum. We conclude that the ground state is in the universality class of the Moore-Read Pfaffian state, rather than the anti-Pfaffian, for ? < ?c(w), where ?c(w) is a w-dependent critical value 0.6 ? ?c(w) ? 1. We observe that both Landau-level mixing and nonzero width suppress the excitation gap, but Landau-level mixing has a larger effect in this regard. Our findings have important implications for the identification of non-Abelian fractional quantum Hall states.

@article{
 title = {Emergent kinetics and fractionalized charge in 1d spin-orbit coupled flatband optical lattices},
 type = {article},
 year = {2014},
 pages = {110404},
 volume = {112},
 websites = {http://link.aps.org/doi/10.1103/PhysRevLett.112.110404},
 month = {3},
 day = {18},
 id = {8ca0de61-0242-3fd3-a728-509a1c7217fb},
 created = {2017-12-12T20:22:21.905Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.713Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lin2014},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Recent ultracold atomic gas experiments implementing synthetic spin-orbit coupling allow access to flatbands that emphasize interactions. We model spin-orbit coupled fermions in a one-dimensional flatband optical lattice. We introduce an effective Luttinger-liquid theory to show that interactions generate collective excitations with emergent kinetics and fractionalized charge, analogous to properties found in the two-dimensional fractional quantum Hall regime. Observation of these excitations would provide an important platform for exploring exotic quantum states derived solely from interactions.},
 bibtype = {article},
 author = {Lin, Fei and Zhang, Chuanwei and Scarola, V. W.},
 doi = {10.1103/PhysRevLett.112.110404},
 journal = {Physical Review Letters},
 number = {11}
}

Recent ultracold atomic gas experiments implementing synthetic spin-orbit coupling allow access to flatbands that emphasize interactions. We model spin-orbit coupled fermions in a one-dimensional flatband optical lattice. We introduce an effective Luttinger-liquid theory to show that interactions generate collective excitations with emergent kinetics and fractionalized charge, analogous to properties found in the two-dimensional fractional quantum Hall regime. Observation of these excitations would provide an important platform for exploring exotic quantum states derived solely from interactions.

@article{
 title = {Wave-function vortex attachment via matrix products: Application to atomic Fermi gases in flat spin-orbit bands},
 type = {article},
 year = {2014},
 pages = {115136},
 volume = {89},
 websites = {http://link.aps.org/doi/10.1103/PhysRevB.89.115136},
 month = {3},
 id = {db636dd9-12f4-3293-835b-7433d70ef406},
 created = {2017-12-12T20:22:24.674Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:58.281Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2014},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Variational wave functions that introduce zeros (vortices) to screen repulsive interactions are typically difficult to verify in unbiased microscopic calculations. An approach is constructed to insert vortices into ansatz wave functions using a matrix-product representation. This approach opens the door to validation of a broad class of Jastrow-based wave functions. The formalism is applied to a model motivated by experiments on ultracold atomic gases in the presence of synthetic spin-orbit coupling. Validated wave functions show that vortices in atomic Fermi gases with flat Rashba spin-orbit bands cluster near the system center and should therefore be directly visible in time-of-flight imaging. © 2014 American Physical Society.},
 bibtype = {article},
 author = {Scarola, V. W.},
 doi = {10.1103/PhysRevB.89.115136},
 journal = {Physical Review B},
 number = {11}
}

Variational wave functions that introduce zeros (vortices) to screen repulsive interactions are typically difficult to verify in unbiased microscopic calculations. An approach is constructed to insert vortices into ansatz wave functions using a matrix-product representation. This approach opens the door to validation of a broad class of Jastrow-based wave functions. The formalism is applied to a model motivated by experiments on ultracold atomic gases in the presence of synthetic spin-orbit coupling. Validated wave functions show that vortices in atomic Fermi gases with flat Rashba spin-orbit bands cluster near the system center and should therefore be directly visible in time-of-flight imaging. © 2014 American Physical Society.

@article{
 title = {Néel temperature and thermodynamics of the half-filled three-dimensional Hubbard model by diagrammatic determinant Monte Carlo},
 type = {article},
 year = {2013},
 pages = {205102},
 volume = {87},
 websites = {http://link.aps.org/doi/10.1103/PhysRevB.87.205102},
 month = {5},
 id = {d2413406-9fad-373f-a2cc-31e0859982ab},
 created = {2017-12-12T20:22:22.680Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.452Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Kozik2013},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We study thermodynamics of the 3D Hubbard model at half filling on approach to the N\'eel transition by means of large-scale unbiased Diagrammatic Determinant Monte Carlo simulations. We obtain the transition temperature in the strongly correlated regime, as well as temperature dependence of energy, entropy, double occupancy, and the nearest-neighbor spin correlation function. Our results improve the accuracy of previous unbiased studies and present accurate benchmarks in the ongoing effort to realize the antiferromagnetic state of matter with ultracold atoms in optical lattices.},
 bibtype = {article},
 author = {Kozik, E. and Burovski, E. and Scarola, V. W. and Troyer, M.},
 doi = {10.1103/PhysRevB.87.205102},
 journal = {Physical Review B},
 number = {20}
}

We study thermodynamics of the 3D Hubbard model at half filling on approach to the N\'eel transition by means of large-scale unbiased Diagrammatic Determinant Monte Carlo simulations. We obtain the transition temperature in the strongly correlated regime, as well as temperature dependence of energy, entropy, double occupancy, and the nearest-neighbor spin correlation function. Our results improve the accuracy of previous unbiased studies and present accurate benchmarks in the ongoing effort to realize the antiferromagnetic state of matter with ultracold atoms in optical lattices.

@article{
 title = {Enhancing the thermal stability of Majorana fermions with redundancy using dipoles in optical lattices},
 type = {article},
 year = {2013},
 pages = {220401},
 volume = {111},
 websites = {http://link.aps.org/doi/10.1103/PhysRevLett.111.220401},
 month = {11},
 day = {25},
 id = {119370cf-cc28-3be2-88e4-8892691259aa},
 created = {2017-12-12T20:22:26.179Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:22.485Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lin2013},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Pairing between spinless fermions can generate Majorana fermion excitations that exhibit intriguing properties arising from nonlocal correlations. But, simple models indicate that nonlocal correlation between Majorana fermions becomes unstable at nonzero temperatures. We address this issue by showing that anisotropic interactions between dipolar fermions in optical lattices can be used to significantly enhance thermal stability. We construct a model of oriented dipolar fermions in a square optical lattice. We find that domains established by strong interactions exhibit enhanced correlation between Majorana fermions over large distances and long times even at finite temperatures, suitable for stable redundancy encoding of quantum information. Our approach can be generalized to a variety of configurations and other systems, such as quantum wire arrays. © 2013 American Physical Society.},
 bibtype = {article},
 author = {Lin, Fei and Scarola, V. W.},
 doi = {10.1103/PhysRevLett.111.220401},
 journal = {Physical Review Letters},
 number = {22}
}

Pairing between spinless fermions can generate Majorana fermion excitations that exhibit intriguing properties arising from nonlocal correlations. But, simple models indicate that nonlocal correlation between Majorana fermions becomes unstable at nonzero temperatures. We address this issue by showing that anisotropic interactions between dipolar fermions in optical lattices can be used to significantly enhance thermal stability. We construct a model of oriented dipolar fermions in a square optical lattice. We find that domains established by strong interactions exhibit enhanced correlation between Majorana fermions over large distances and long times even at finite temperatures, suitable for stable redundancy encoding of quantum information. Our approach can be generalized to a variety of configurations and other systems, such as quantum wire arrays. © 2013 American Physical Society.

@article{
 title = {Thermal versus quantum fluctuations of optical-lattice fermions},
 type = {article},
 year = {2012},
 pages = {33644},
 volume = {85},
 websites = {http://link.aps.org/doi/10.1103/PhysRevA.85.033644},
 id = {b7d53cfb-2471-32ea-8749-6b9b77a3ea50},
 created = {2017-12-12T20:22:23.554Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:56.103Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Campo2012},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We show that, for fermionic atoms in a one-dimensional optical lattice, the fraction of atoms in doubly occupied sites is a highly nonmonotonic function of temperature. We demonstrate that this property persists even in the presence of realistic harmonic confinement, and that it leads to a suppression of entropy at intermediate temperatures that offers a route to adiabatic cooling. Our interpretation of the suppression is that such intermediate temperatures are simultaneously too high for quantum coherence and too low for significant thermal excitation of double occupancy thus offering a clear indicator of the onset of quantum fluctuations.},
 bibtype = {article},
 author = {Campo, V. L. and Capelle, K. and Hooley, C. and Quintanilla, J. and Scarola, V. W.},
 doi = {10.1103/PhysRevA.85.033644},
 journal = {Physical Review A},
 number = {3}
}

We show that, for fermionic atoms in a one-dimensional optical lattice, the fraction of atoms in doubly occupied sites is a highly nonmonotonic function of temperature. We demonstrate that this property persists even in the presence of realistic harmonic confinement, and that it leads to a suppression of entropy at intermediate temperatures that offers a route to adiabatic cooling. Our interpretation of the suppression is that such intermediate temperatures are simultaneously too high for quantum coherence and too low for significant thermal excitation of double occupancy thus offering a clear indicator of the onset of quantum fluctuations.

@article{
 title = {Probing a topological quantum critical point in semiconductor- superconductor heterostructures},
 type = {article},
 year = {2012},
 pages = {1-7},
 volume = {85},
 websites = {http://link.aps.org/doi/10.1103/PhysRevB.85.155302},
 id = {f3010b70-ea9d-37e7-85b9-572960305a7f},
 created = {2017-12-12T20:22:24.935Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.843Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Tewari2011a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Quantum ground states on the nontrivial side of a topological quantum critical point (TQCP) have unique properties that make them attractive candidates for quantum information applications. A recent example is provided by s-wave superconductivity on a semiconductor platform, which is tuned through a TQCP to a topological superconducting (TS) state by an external Zeeman field. Despite many attractive features of TS states, TQCPs themselves do not break any symmetries, making it impossible to distinguish the TS state from a regular superconductor in conventional bulk measurements. Here we show that for the semiconductor TQCP this problem can be overcome by tracking suitable bulk transport properties across the topological quantum critical regime itself. The universal low-energy effective theory and the scaling form of the relevant susceptibilities also provide a useful theoretical framework in which to understand the topological transitions in semiconductor heterostructures. Based on our theory, specific bulk measurements are proposed here in order to characterize the novel TQCP in semiconductor heterostructures. © 2012 American Physical Society.},
 bibtype = {article},
 author = {Tewari, Sumanta and Sau, J. D. and Scarola, V. W. and Zhang, Chuanwei and Das Sarma, S.},
 doi = {10.1103/PhysRevB.85.155302},
 journal = {Physical Review B},
 number = {15}
}

Quantum ground states on the nontrivial side of a topological quantum critical point (TQCP) have unique properties that make them attractive candidates for quantum information applications. A recent example is provided by s-wave superconductivity on a semiconductor platform, which is tuned through a TQCP to a topological superconducting (TS) state by an external Zeeman field. Despite many attractive features of TS states, TQCPs themselves do not break any symmetries, making it impossible to distinguish the TS state from a regular superconductor in conventional bulk measurements. Here we show that for the semiconductor TQCP this problem can be overcome by tracking suitable bulk transport properties across the topological quantum critical regime itself. The universal low-energy effective theory and the scaling form of the relevant susceptibilities also provide a useful theoretical framework in which to understand the topological transitions in semiconductor heterostructures. Based on our theory, specific bulk measurements are proposed here in order to characterize the novel TQCP in semiconductor heterostructures. © 2012 American Physical Society.

@article{
 title = {Percolation-enhanced supersolids in the extended Bose-Hubbard model},
 type = {article},
 year = {2012},
 pages = {20501},
 volume = {85},
 websites = {http://prb.aps.org/abstract/PRB/v85/i2/e020501},
 id = {7ab87705-043b-308a-8bce-714ad31ed178},
 created = {2017-12-12T20:22:25.233Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:07.048Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Kemburi2012},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We theoretically study the stability of lattice supersolid states\nin the extended Bose-Hubbard model with bounded spatial disorder.\nWe construct a disorder mean-field theory and compare with quantum\nMonte Carlo calculations. The supersolid survives weak disorder on\nthe simple cubic lattice. We also find that increasing disorder strength\ncan transform a lattice solid into a supersolid as it tends to percolate\nthrough the disorder landscape.},
 bibtype = {article},
 author = {Kemburi, B. and Scarola, V.},
 doi = {10.1103/PhysRevB.85.020501},
 journal = {Physical Review B},
 number = {2}
}

We theoretically study the stability of lattice supersolid states\nin the extended Bose-Hubbard model with bounded spatial disorder.\nWe construct a disorder mean-field theory and compare with quantum\nMonte Carlo calculations. The supersolid survives weak disorder on\nthe simple cubic lattice. We also find that increasing disorder strength\ncan transform a lattice solid into a supersolid as it tends to percolate\nthrough the disorder landscape.

@article{
 title = {Models of strong interaction in flat-band graphene nanoribbons: Magnetic quantum crystals},
 type = {article},
 year = {2012},
 pages = {75438},
 volume = {85},
 websites = {http://link.aps.org/doi/10.1103/PhysRevB.85.075438},
 id = {69f6c9fc-5b9a-36ce-ba5e-f00b1b3d7861},
 created = {2017-12-12T20:22:25.978Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:56.567Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Wang2012},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Graphene-based nanostructures exhibit flat electronic energy bands in their single-particle spectrum. We consider interacting electrons in flat bands of zigzag nanoribbons. We present a protocol for flat-band projection that yields interaction-only tight-binding models. We argue that, at low densities, flat bands can delocalize single-particle basis states to support ferromagnetic quantum crystal ground states. © 2012 American Physical Society.},
 bibtype = {article},
 author = {Wang, Hao and Scarola, V. W.},
 doi = {10.1103/PhysRevB.85.075438},
 journal = {Physical Review B},
 number = {7}
}

Graphene-based nanostructures exhibit flat electronic energy bands in their single-particle spectrum. We consider interacting electrons in flat bands of zigzag nanoribbons. We present a protocol for flat-band projection that yields interaction-only tight-binding models. We argue that, at low densities, flat bands can delocalize single-particle basis states to support ferromagnetic quantum crystal ground states. © 2012 American Physical Society.

@article{
 title = {Boson core compressibility},
 type = {article},
 year = {2012},
 pages = {043610},
 volume = {85},
 websites = {http://link.aps.org/doi/10.1103/PhysRevA.85.043610},
 month = {4},
 day = {16},
 id = {7fced592-d845-3a43-8f9a-4840ad3cc1b5},
 created = {2017-12-12T20:22:26.934Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:57.942Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Khorramzadeh2012},
 source_type = {JOUR},
 folder_uuids = {57d52dd9-09fc-4a98-a641-4768de6b0239},
 private_publication = {false},
 abstract = {Strongly interacting atoms trapped in optical lattices can be used to explore phase diagrams of Hubbard models. Spatial inhomogeneity due to trapping typically obscures distinguishing observables. We propose that measures using boson double occupancy avoid trapping effects to reveal two key correlation functions. We define a boson core compressibility and core superfluid stiffness in terms of double occupancy. We use quantum Monte Carlo on the Bose-Hubbard model to empirically show that these quantities intrinsically eliminate edge effects to reveal correlations near the trap center. The boson core compressibility offers a generally applicable tool that can be used to experimentally map out phase transitions between compressible and incompressible states. © 2012 American Physical Society.},
 bibtype = {article},
 author = {Khorramzadeh, Y. and Lin, Fei and Scarola, V. W.},
 doi = {10.1103/PhysRevA.85.043610},
 journal = {Physical Review A},
 number = {4}
}

Strongly interacting atoms trapped in optical lattices can be used to explore phase diagrams of Hubbard models. Spatial inhomogeneity due to trapping typically obscures distinguishing observables. We propose that measures using boson double occupancy avoid trapping effects to reveal two key correlation functions. We define a boson core compressibility and core superfluid stiffness in terms of double occupancy. We use quantum Monte Carlo on the Bose-Hubbard model to empirically show that these quantities intrinsically eliminate edge effects to reveal correlations near the trap center. The boson core compressibility offers a generally applicable tool that can be used to experimentally map out phase transitions between compressible and incompressible states. © 2012 American Physical Society.

@article{
 title = {The ALPS project release 2.0: Open source software for strongly correlated systems},
 type = {article},
 year = {2011},
 keywords = {classical Monte Carlo simulations,density matrix renormalization group calculations,quantum Monte Carlo simulations,quantum phase transitions (theory)},
 pages = {P05001},
 volume = {2011},
 websites = {http://dx.doi.org/10.1088/1742-5468/2011/05/P05001},
 month = {5},
 day = {4},
 id = {448df003-1a6a-33a9-9ff6-c2f283088ca2},
 created = {2017-12-12T20:22:21.468Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-08-17T14:41:39.471Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Bauer2011},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We present release 2.0 of the ALPS (Algorithms and Libraries for Physics Simulations) project, an open source software project to develop libraries and application programs for the simulation of strongly correlated quantum lattice models such as quantum magnets, lattice bosons, and strongly correlated fermion systems. The code development is centered on common XML and HDF5 data formats, libraries to simplify and speed up code development, common evaluation and plotting tools, and simulation programs. The programs enable non-experts to start carrying out serial or parallel numerical simulations by providing basic implementations of the important algorithms for quantum lattice models: classical and quantum Monte Carlo (QMC) using non-local updates, extended ensemble simulations, exact and full diagonalization (ED), the density matrix renormalization group (DMRG) both in a static version and a dynamic time-evolving block decimation (TEBD) code, and quantum Monte Carlo solvers for dynamical mean field theory (DMFT). The ALPS libraries provide a powerful framework for programers to develop their own applications, which, for instance, greatly simplify the steps of porting a serial code onto a parallel, distributed memory machine. Major changes in release 2.0 include the use of HDF5 for binary data, evaluation tools in Python, support for the Windows operating system, the use of CMake as build system and binary installation packages for Mac OS X and Windows, and integration with the VisTrails workflow provenance tool. The software is available from our web server at http://alps.comp-phys.org/.},
 bibtype = {article},
 author = {Bauer, B. and Carr, L. D. and Evertz, H. G. and Feiguin, A. and Freire, J. and Fuchs, S. and Gamper, L. and Gukelberger, J. and Gull, E. and Guertler, S. and Hehn, A. and Igarashi, R. and Isakov, S. V. and Koop, D. and Ma, P. N. and Mates, P. and Matsuo, H. and Parcollet, O. and Pawłowski, G. and Picon, J. D. and Pollet, L. and Santos, E. and Scarola, V. W. and Schollwöck, U. and Silva, C. and Surer, B. and Todo, S. and Trebst, S. and Troyer, M. and Wall, M. L. and Werner, P. and Wessel, S.},
 doi = {10.1088/1742-5468/2011/05/P05001},
 journal = {Journal of Statistical Mechanics: Theory and Experiment},
 number = {5}
}

We present release 2.0 of the ALPS (Algorithms and Libraries for Physics Simulations) project, an open source software project to develop libraries and application programs for the simulation of strongly correlated quantum lattice models such as quantum magnets, lattice bosons, and strongly correlated fermion systems. The code development is centered on common XML and HDF5 data formats, libraries to simplify and speed up code development, common evaluation and plotting tools, and simulation programs. The programs enable non-experts to start carrying out serial or parallel numerical simulations by providing basic implementations of the important algorithms for quantum lattice models: classical and quantum Monte Carlo (QMC) using non-local updates, extended ensemble simulations, exact and full diagonalization (ED), the density matrix renormalization group (DMRG) both in a static version and a dynamic time-evolving block decimation (TEBD) code, and quantum Monte Carlo solvers for dynamical mean field theory (DMFT). The ALPS libraries provide a powerful framework for programers to develop their own applications, which, for instance, greatly simplify the steps of porting a serial code onto a parallel, distributed memory machine. Major changes in release 2.0 include the use of HDF5 for binary data, evaluation tools in Python, support for the Windows operating system, the use of CMake as build system and binary installation packages for Mac OS X and Windows, and integration with the VisTrails workflow provenance tool. The software is available from our web server at http://alps.comp-phys.org/.

@article{
 title = {Thermodynamics of the three-dimensional Hubbard model: Implications for cooling cold atomic gases in optical lattices},
 type = {article},
 year = {2011},
 pages = {23606},
 volume = {83},
 websites = {http://link.aps.org/doi/10.1103/PhysRevA.83.023606},
 id = {b894b2cb-2456-3822-912c-21d611d5cac3},
 created = {2017-12-12T20:22:21.768Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:00.519Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {DeLeo2011},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We present a comprehensive study of the thermodynamic properties of the three-dimensional fermionic Hubbard model, with application to cold fermionic atoms subject to an optical lattice and a trapping potential. Our study is focused on the temperature range of current experimental interest. We employ two theoretical methods - dynamical mean-field theory and high-temperature series - and perform comparative benchmarks to delimitate their respective range of validity. Special attention is devoted to understand the implications that thermodynamic properties of this system have on cooling. Considering the distribution function of local occupancies in the inhomogeneous lattice, we show that, under adiabatic evolution, the variation of any observable (e.g., temperature) can be conveniently disentangled into two distinct contributions. The first contribution is due to the redistribution of atoms in the trap during the evolution, while the second one comes from the intrinsic change of the observable. Finally, we provide a simplified picture of the cooling procedure recently proposed in J.-S. Bernier et al., Phys. Rev. A 79, 061601 (2009) by applying this method to an idealized model.},
 bibtype = {article},
 author = {De Leo, Lorenzo and Bernier, Jean Sébastien and Kollath, Corinna and Georges, Antoine and Scarola, Vito W.},
 doi = {10.1103/PhysRevA.83.023606},
 journal = {Physical Review A},
 number = {2}
}

We present a comprehensive study of the thermodynamic properties of the three-dimensional fermionic Hubbard model, with application to cold fermionic atoms subject to an optical lattice and a trapping potential. Our study is focused on the temperature range of current experimental interest. We employ two theoretical methods - dynamical mean-field theory and high-temperature series - and perform comparative benchmarks to delimitate their respective range of validity. Special attention is devoted to understand the implications that thermodynamic properties of this system have on cooling. Considering the distribution function of local occupancies in the inhomogeneous lattice, we show that, under adiabatic evolution, the variation of any observable (e.g., temperature) can be conveniently disentangled into two distinct contributions. The first contribution is due to the redistribution of atoms in the trap during the evolution, while the second one comes from the intrinsic change of the observable. Finally, we provide a simplified picture of the cooling procedure recently proposed in J.-S. Bernier et al., Phys. Rev. A 79, 061601 (2009) by applying this method to an idealized model.

@article{
 title = {Jastrow-correlated wave functions for flat-band lattices},
 type = {article},
 year = {2011},
 pages = {245109},
 volume = {83},
 websites = {http://dx.doi.org/10.1103/PhysRevB.83.245109},
 id = {cf06887f-c2d9-3dd6-80c5-e41e720f10d1},
 created = {2017-12-12T20:22:21.991Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:00.792Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Wang2011a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {The electronic band structure of many compounds, e.g., carbon-based structures, can exhibit essentially no dispersion. Models of electrons in flat-band lattices define nonperturbative strongly correlated problems by default. We construct a set of Jastrow-correlated ansatz wavefunctions to capture the low energy physics of interacting particles in flat bands. We test the ansatz in a simple Coulomb model of spinless electrons in a honeycomb ribbon. We find that the wavefunction accurately captures the ground state in a transition from a crystal to a uniform quantum liquid. © 2011 American Physical Society.},
 bibtype = {article},
 author = {Wang, Hao and Scarola, V. W.},
 doi = {10.1103/PhysRevB.83.245109},
 journal = {Physical Review B},
 number = {24}
}

The electronic band structure of many compounds, e.g., carbon-based structures, can exhibit essentially no dispersion. Models of electrons in flat-band lattices define nonperturbative strongly correlated problems by default. We construct a set of Jastrow-correlated ansatz wavefunctions to capture the low energy physics of interacting particles in flat bands. We test the ansatz in a simple Coulomb model of spinless electrons in a honeycomb ribbon. We find that the wavefunction accurately captures the ground state in a transition from a crystal to a uniform quantum liquid. © 2011 American Physical Society.

@article{
 title = {Identifying quantum topological phases through statistical correlation},
 type = {article},
 year = {2011},
 pages = {115119},
 volume = {83},
 websites = {http://dx.doi.org/10.1103/PhysRevB.83.115119},
 id = {8f0ef47a-0280-3491-9465-58cd4bea2089},
 created = {2017-12-12T20:22:27.858Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.398Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Wang2011},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We theoretically examine the use of a statistical distance measure, the indistinguishability, as a generic tool for the identification of topological order. We apply this measure to the toric code and two fractional quantum Hall models. We find that topologically ordered states can be identified with the indistinguishability for both models. Calculations with the indistinguishability also underscore a key distinction between symmetries that underlie topological order in the toric code and quantum Hall models.},
 bibtype = {article},
 author = {Wang, Hao and Bauer, B. and Troyer, M. and Scarola, V. W.},
 doi = {10.1103/PhysRevB.83.115119},
 journal = {Physical Review B},
 number = {11}
}

We theoretically examine the use of a statistical distance measure, the indistinguishability, as a generic tool for the identification of topological order. We apply this measure to the toric code and two fractional quantum Hall models. We find that topologically ordered states can be identified with the indistinguishability for both models. Calculations with the indistinguishability also underscore a key distinction between symmetries that underlie topological order in the toric code and quantum Hall models.

@article{
 title = {Quantitative determination of temperature in the approach to magnetic order of ultracold fermions in an optical lattice},
 type = {article},
 year = {2010},
 pages = {180401},
 volume = {104},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.104.180401},
 month = {5},
 day = {6},
 id = {5ee70647-2ff1-31fc-87cd-dfe93010fe13},
 created = {2017-12-12T20:22:22.319Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-02-11T23:51:26.358Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Jordens2010},
 source_type = {JOUR},
 folder_uuids = {bf1472c4-b5ce-4285-af1e-2ae88f411bbf},
 private_publication = {false},
 abstract = {We perform a quantitative simulation of the repulsive Fermi-Hubbard model using an ultracold gas trapped in an optical lattice. The entropy of the system is determined by comparing accurate measurements of the equilibrium double occupancy with theoretical calculations over a wide range of parameters. We demonstrate the applicability of both high-temperature series and dynamical mean-field theory to obtain quantitative agreement with the experimental data. The reliability of the entropy determination is confirmed by a comprehensive analysis of all systematic errors. In the center of the Mott insulating cloud we obtain an entropy per atom as low as 0.77kB which is about twice as large as the entropy at the Neel transition. The corresponding temperature depends on the atom number and for small fillings reaches values on the order of the tunneling energy.},
 bibtype = {article},
 author = {Jördens, R. and Tarruell, L. and Greif, D. and Uehlinger, T. and Strohmaier, N. and Moritz, H. and Esslinger, T. and De Leo, L. and Kollath, C. and Georges, A. and Scarola, V. and Pollet, L. and Burovski, E. and Kozik, E. and Troyer, M.},
 doi = {10.1103/PhysRevLett.104.180401},
 journal = {Physical Review Letters},
 number = {18}
}

We perform a quantitative simulation of the repulsive Fermi-Hubbard model using an ultracold gas trapped in an optical lattice. The entropy of the system is determined by comparing accurate measurements of the equilibrium double occupancy with theoretical calculations over a wide range of parameters. We demonstrate the applicability of both high-temperature series and dynamical mean-field theory to obtain quantitative agreement with the experimental data. The reliability of the entropy determination is confirmed by a comprehensive analysis of all systematic errors. In the center of the Mott insulating cloud we obtain an entropy per atom as low as 0.77kB which is about twice as large as the entropy at the Neel transition. The corresponding temperature depends on the atom number and for small fillings reaches values on the order of the tunneling energy.

@article{
 title = {Distinguishing phases with ansatz wave functions},
 type = {article},
 year = {2010},
 pages = {85118},
 volume = {81},
 websites = {http://dx.doi.org/10.1103/PhysRevB.81.085118},
 id = {8f0d0fe0-0cd6-39cf-99ae-aeca958977fa},
 created = {2017-12-12T20:22:22.523Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:58.523Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Bauer2010},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We propose an indistinguishability measure for assessment of ansatz wave functions with numerically determined wave functions. The measure efficiently compares all correlation functions of two states and can therefore be used to distinguish phases by defining correlator classes for ansatz wave functions. It also allows identification of quantum critical points. We demonstrate the approach for the transverse Ising and bilinear-biquadratic Heisenberg models, using the matrix-product state formalism with the time-evolving block decimation algorithm.},
 bibtype = {article},
 author = {Bauer, B. and Troyer, M. and Scarola, V. W. and Whaley, K. B.},
 doi = {10.1103/PhysRevB.81.085118},
 journal = {Physical Review B},
 number = {8}
}

We propose an indistinguishability measure for assessment of ansatz wave functions with numerically determined wave functions. The measure efficiently compares all correlation functions of two states and can therefore be used to distinguish phases by defining correlator classes for ansatz wave functions. It also allows identification of quantum critical points. We demonstrate the approach for the transverse Ising and bilinear-biquadratic Heisenberg models, using the matrix-product state formalism with the time-evolving block decimation algorithm.

@article{
 title = {Subband engineering even-denominator quantum Hall states},
 type = {article},
 year = {2010},
 pages = {121304},
 volume = {82},
 websites = {https://link.aps.org/doi/10.1103/PhysRevB.82.121304},
 month = {9},
 day = {9},
 id = {35515cef-ef0b-3c9b-af35-e17dc5977276},
 created = {2017-12-12T20:22:22.856Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-11T13:34:57.541Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2010},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Proposed even-denominator fractional quantum Hall effect (FQHE) states suggest the possibility of excitations with non-Abelian braid statistics. Recent experiments on wide square quantum wells observe even-denominator FQHE even under electrostatic tilt. We theoretically analyze these structures and develop a procedure to accurately test proposed quantum Hall wavefunctions. We find that tilted wells favor partial subband polarization to yield Abelian even-denominator states. Our results show that tilting quantum wells effectively engineers different interaction potentials allowing exploration of a wide variety of even-denominator states.},
 bibtype = {article},
 author = {Scarola, V. W. and May, C. and Peterson, M. R. and Troyer, M.},
 doi = {10.1103/PhysRevB.82.121304},
 journal = {Physical Review B},
 number = {12}
}

Proposed even-denominator fractional quantum Hall effect (FQHE) states suggest the possibility of excitations with non-Abelian braid statistics. Recent experiments on wide square quantum wells observe even-denominator FQHE even under electrostatic tilt. We theoretically analyze these structures and develop a procedure to accurately test proposed quantum Hall wavefunctions. We find that tilted wells favor partial subband polarization to yield Abelian even-denominator states. Our results show that tilting quantum wells effectively engineers different interaction potentials allowing exploration of a wide variety of even-denominator states.

@article{
 title = {Stroboscopic generation of topological protection},
 type = {article},
 year = {2010},
 pages = {230501},
 volume = {104},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.104.230501},
 month = {6},
 day = {8},
 id = {4616aa06-a6c4-3afa-af79-d8ec1a1bd48c},
 created = {2017-12-12T20:22:24.317Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.494Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Herdman2010},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Trapped neutral atoms offer a powerful route to robust simulation of complex quantum systems. We present here a stroboscopic scheme for realization of a Hamiltonian with n-body interactions on a set of neutral atoms trapped in an addressable optical lattice, using only 1- and 2-body physical operations together with a dissipative mechanism that allows thermalization to finite temperature or cooling to the ground state. We demonstrate this scheme with application to the toric code Hamiltonian, ground states of which can be used to robustly store quantum information when coupled to a low temperature reservoir.},
 bibtype = {article},
 author = {Herdman, C. M. and Young, Kevin C. and Scarola, V. W. and Sarovar, Mohan and Whaley, K. B.},
 doi = {10.1103/PhysRevLett.104.230501},
 journal = {Physical Review Letters},
 number = {23}
}

Trapped neutral atoms offer a powerful route to robust simulation of complex quantum systems. We present here a stroboscopic scheme for realization of a Hamiltonian with n-body interactions on a set of neutral atoms trapped in an addressable optical lattice, using only 1- and 2-body physical operations together with a dissipative mechanism that allows thermalization to finite temperature or cooling to the ground state. We demonstrate this scheme with application to the toric code Hamiltonian, ground states of which can be used to robustly store quantum information when coupled to a low temperature reservoir.

@article{
 title = {Robustness of topologically protected surface states in layering of Bi 2Te3 thin films},
 type = {article},
 year = {2010},
 pages = {186801},
 volume = {105},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.105.186801,https://doi.org/10.1103/PhysRevLett.105.186801},
 id = {f4ae8b8e-677c-3ebb-9a02-b4003ee89ba3},
 created = {2020-06-19T15:33:17.122Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-06-28T00:30:31.289Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Park2010},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Bulk Bi2Te3 is known to be a topological insulator. We investigate surface states of Bi2Te3(111) thin films of one to six quintuple layers using density-functional theory including spin-orbit coupling. We construct a method to identify topologically protected surface states of thin film topological insulators. Applying this method to Bi2Te3 thin films, we find that the topological nature of the surface states remains robust with the film thickness and that the films of three or more quintuple layers have topologically nontrivial surface states, which agrees with experiments.},
 bibtype = {article},
 author = {Park, Kyungwha and Heremans, J. J. and Scarola, V. W. and Minic, Djordje},
 doi = {10.1103/PhysRevLett.105.186801},
 journal = {Physical Review Letters},
 number = {18}
}

Bulk Bi2Te3 is known to be a topological insulator. We investigate surface states of Bi2Te3(111) thin films of one to six quintuple layers using density-functional theory including spin-orbit coupling. We construct a method to identify topologically protected surface states of thin film topological insulators. Applying this method to Bi2Te3 thin films, we find that the topological nature of the surface states remains robust with the film thickness and that the films of three or more quintuple layers have topologically nontrivial surface states, which agrees with experiments.

@article{
 title = {Discerning incompressible and compressible phases of cold atoms in optical lattices},
 type = {article},
 year = {2009},
 pages = {135302},
 volume = {102},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.102.135302},
 month = {3},
 day = {31},
 id = {f4aaad76-1f64-3df0-ac35-f06343bb9a66},
 created = {2017-12-12T20:22:22.071Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.169Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2009},
 source_type = {JOUR},
 folder_uuids = {57d52dd9-09fc-4a98-a641-4768de6b0239},
 private_publication = {false},
 abstract = {Experiments with cold atoms trapped in optical lattices offer the potential to realize a variety of novel phases but suffer from severe spatial inhomogeneity that can obscure signatures of new phases of matter and phase boundaries. We use a high temperature series expansion to show that compressibility in the core of a trapped Fermi-Hubbard system is related to measurements of changes in double occupancy. This core compressibility filters out edge effects, offering a direct probe of compressibility independent of inhomogeneity. A comparison with experiments is made.},
 bibtype = {article},
 author = {Scarola, V. W. and Pollet, L. and Oitmaa, J. and Troyer, M.},
 doi = {10.1103/PhysRevLett.102.135302},
 journal = {Physical Review Letters},
 number = {13}
}

Experiments with cold atoms trapped in optical lattices offer the potential to realize a variety of novel phases but suffer from severe spatial inhomogeneity that can obscure signatures of new phases of matter and phase boundaries. We use a high temperature series expansion to show that compressibility in the core of a trapped Fermi-Hubbard system is related to measurements of changes in double occupancy. This core compressibility filters out edge effects, offering a direct probe of compressibility independent of inhomogeneity. A comparison with experiments is made.

@article{
 title = {Dispersion of the Excitations of Fractional Quantum Hall States},
 type = {article},
 year = {2009},
 pages = {1044-1047},
 volume = {324},
 websites = {http://www.sciencemag.org/cgi/doi/10.1126/science.1171472},
 month = {5},
 day = {22},
 id = {f5f07d4f-da13-3cb5-9d57-072f32ffcdb1},
 created = {2017-12-12T20:22:25.141Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:05.925Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Kukushkin2009},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {The rich correlation physics in two-dimensional (2D) electron systems is governed by the dispersion of its excitations. In the fractional quantum Hall regime, excitations involve fractionally charged quasi particles, which exhibit dispersion minima at large momenta referred to as rotons. These rotons are difficult to access with conventional techniques because of the lack of penetration depth or sample volume. Our method overcomes the limitations of conventional methods and traces the dispersion of excitations across momentum space for buried systems involving small material volume. We used surface acoustic waves, launched across the 2D system, to allow incident radiation to trigger these excitations at large momenta. Optics probed their resonant absorption. Our technique unveils the full dispersion of such excitations of several prominent correlated ground states of the 2D electron system, which has so far been inaccessible for experimentation.},
 bibtype = {article},
 author = {Kukushkin, I. V. and Smet, J. H. and Scarola, V. W. and Umansky, V. and von Klitzing, K.},
 doi = {10.1126/science.1171472},
 journal = {Science},
 number = {5930}
}

The rich correlation physics in two-dimensional (2D) electron systems is governed by the dispersion of its excitations. In the fractional quantum Hall regime, excitations involve fractionally charged quasi particles, which exhibit dispersion minima at large momenta referred to as rotons. These rotons are difficult to access with conventional techniques because of the lack of penetration depth or sample volume. Our method overcomes the limitations of conventional methods and traces the dispersion of excitations across momentum space for buried systems involving small material volume. We used surface acoustic waves, launched across the 2D system, to allow incident radiation to trigger these excitations at large momenta. Optics probed their resonant absorption. Our technique unveils the full dispersion of such excitations of several prominent correlated ground states of the 2D electron system, which has so far been inaccessible for experimentation.

@article{
 title = {Thermal canting of spin-bond order},
 type = {article},
 year = {2009},
 pages = {85113},
 volume = {79},
 websites = {http://dx.doi.org/10.1103/PhysRevB.79.085113},
 id = {42a1f95a-2c73-357a-918b-f46e919b5448},
 created = {2017-12-12T20:22:26.839Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:59.934Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2009a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Magnetism arising from coupled spin and spatial degrees of freedom underlies the properties of a broad array of physical systems. We study here the interplay between correlations in spin and space for the quantum compass model in a finite external field, using quantum Monte Carlo methods. We find that finite temperatures cant the spin and space (bond) correlations, with increasing temperature, even reorienting spin correlations between orthogonal spatial directions. We develop a coupled mean-field theory to understand this effect in terms of the underlying quantum critical properties of crossed Ising chains in transverse fields and an effective field that weakens upon increasing temperature. Thermal canting offers an experimental signature of spin-bond anisotropy.},
 bibtype = {article},
 author = {Scarola, V. W. and Whaley, K. B. and Troyer, M.},
 doi = {10.1103/PhysRevB.79.085113},
 journal = {Physical Review B},
 number = {8}
}

Magnetism arising from coupled spin and spatial degrees of freedom underlies the properties of a broad array of physical systems. We study here the interplay between correlations in spin and space for the quantum compass model in a finite external field, using quantum Monte Carlo methods. We find that finite temperatures cant the spin and space (bond) correlations, with increasing temperature, even reorienting spin correlations between orthogonal spatial directions. We develop a coupled mean-field theory to understand this effect in terms of the underlying quantum critical properties of crossed Ising chains in transverse fields and an effective field that weakens upon increasing temperature. Thermal canting offers an experimental signature of spin-bond anisotropy.

@article{
 title = {Emulating non-Abelian topological matter in cold-atom optical lattices},
 type = {article},
 year = {2008},
 pages = {23612},
 volume = {77},
 websites = {http://dx.doi.org/10.1103/PhysRevA.77.023612},
 id = {eabd2c5d-fcc6-334b-be63-27e09f0cd81c},
 created = {2017-12-12T20:22:26.358Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:58.448Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2008},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Certain proposed extended Bose-Hubbard models may exhibit topologically ordered ground states with excitations obeying non-Abelian braid statistics. A sufficient tuning of Hubbard parameters could yield excitation braiding rules allowing implementation of a universal set of topologically protected quantum gates. We discuss potential difficulties in realizing a model with a proposed non-Abelian topologically ordered ground state using optical lattices containing bosonic dipoles. Our direct implementation scheme does not realize the necessary anisotropic hopping, anisotropic interactions, and low temperatures.},
 bibtype = {article},
 author = {Scarola, V. W. and Das Sarma, S.},
 doi = {10.1103/PhysRevA.77.023612},
 journal = {Physical Review A},
 number = {2}
}

Certain proposed extended Bose-Hubbard models may exhibit topologically ordered ground states with excitations obeying non-Abelian braid statistics. A sufficient tuning of Hubbard parameters could yield excitation braiding rules allowing implementation of a universal set of topologically protected quantum gates. We discuss potential difficulties in realizing a model with a proposed non-Abelian topologically ordered ground state using optical lattices containing bosonic dipoles. Our direct implementation scheme does not realize the necessary anisotropic hopping, anisotropic interactions, and low temperatures.

@article{
 title = {Initializing a quantum register from Mott-insulator states in optical lattices},
 type = {article},
 year = {2007},
 pages = {60301},
 volume = {75},
 websites = {http://dx.doi.org/10.1103/PhysRevA.75.060301},
 id = {5e636345-5bcf-37e5-a80a-ed388a82ec00},
 created = {2017-12-12T20:22:22.958Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.300Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Zhang2007},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We propose a technique to measure multi-spin correlation functions of arbitrary range as determined by the ground states of spinful cold atoms in optical lattices. We show that an observation of the atomic version of the Stokes parameters, using focused lasers and microwave pulsing, can be related to $n$-spin correlators. We discuss the possibility of detecting not only ground state static spin correlations, but also time-dependent spin wave dynamics as a demonstrative example using our proposed technique.},
 bibtype = {article},
 author = {Zhang, Chuanwei and Scarola, V. W. and Sarma, S. Das},
 doi = {10.1103/PhysRevA.75.060301},
 journal = {Physical Review A},
 number = {6}
}

We propose a technique to measure multi-spin correlation functions of arbitrary range as determined by the ground states of spinful cold atoms in optical lattices. We show that an observation of the atomic version of the Stokes parameters, using focused lasers and microwave pulsing, can be related to $n$-spin correlators. We discuss the possibility of detecting not only ground state static spin correlations, but also time-dependent spin wave dynamics as a demonstrative example using our proposed technique.

@article{
 title = {Edge transport in 2D cold atom optical lattices},
 type = {article},
 year = {2007},
 pages = {210403},
 volume = {98},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.98.210403},
 id = {4d47c1a8-4721-3548-af7f-db9bc0e76489},
 created = {2017-12-12T20:22:23.129Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.923Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2007},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We theoretically study the observable response of edge currents in two dimensional cold atom optical lattices. As an example we use Gutzwiller mean-field theory to relate persistent edge currents surrounding a Mott insulator in a slowly rotating trapped Bose-Hubbard system to time of flight measurements. We briefly discuss an application, the detection of Chern number using edge currents of a topologically ordered optical lattice insulator.},
 bibtype = {article},
 author = {Scarola, V. W. and Das Sarma, S.},
 doi = {10.1103/PhysRevLett.98.210403},
 journal = {Physical Review Letters},
 number = {21}
}

We theoretically study the observable response of edge currents in two dimensional cold atom optical lattices. As an example we use Gutzwiller mean-field theory to relate persistent edge currents surrounding a Mott insulator in a slowly rotating trapped Bose-Hubbard system to time of flight measurements. We briefly discuss an application, the detection of Chern number using edge currents of a topologically ordered optical lattice insulator.

@article{
 title = {Probing n-spin correlations in optical lattices},
 type = {article},
 year = {2007},
 keywords = {r05180},
 pages = {023605},
 volume = {76},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.76.023605},
 id = {59d883dc-a562-3c74-b3b5-da3ad63c2f66},
 created = {2017-12-12T20:22:25.797Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.358Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Zhang2007c},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We propose a technique to measure multispin correlation functions of arbitrary range as determined by the ground states of spinful cold atoms in optical lattices. We show that an observation of the atomic version of the Stokes parameters, using focused lasers and microwave pulsing, can be related to n-spin correlators. We discuss the possibility of detecting not only ground state static spin correlations, but also time-dependent spin-wave dynamics as a demonstrative example using our proposed technique.},
 bibtype = {article},
 author = {Zhang, Chuanwei and Scarola, V. W. and Das Sarma, S.},
 doi = {10.1103/PhysRevA.76.023605},
 journal = {Physical Review A},
 number = {2}
}

We propose a technique to measure multispin correlation functions of arbitrary range as determined by the ground states of spinful cold atoms in optical lattices. We show that an observation of the atomic version of the Stokes parameters, using focused lasers and microwave pulsing, can be related to n-spin correlators. We discuss the possibility of detecting not only ground state static spin correlations, but also time-dependent spin-wave dynamics as a demonstrative example using our proposed technique.

@article{
 title = {Anyonic braiding in optical lattices},
 type = {article},
 year = {2007},
 pages = {18415-18420},
 volume = {104},
 websites = {http://www.pnas.org/cgi/doi/10.1073/pnas.0709075104},
 month = {11},
 publisher = {National Academy of Sciences},
 day = {20},
 id = {4bc9b441-7283-311a-9fa3-16c40448d67f},
 created = {2017-12-12T20:22:26.524Z},
 accessed = {2017-11-17},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.355Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Zhang2007b},
 folder_uuids = {4dea6cad-aea6-4b8d-8508-752e5cfc5357},
 private_publication = {false},
 abstract = {Topological quantum states of matter, both Abelian and non-Abelian, are characterized by excitations whose wavefunctions undergo nontrivial statistical transformations as one excitation is moved (braided) around another. Topological quantum computation proposes to use the topological protection and the braiding statistics of a non-Abelian topological state to perform quantum computation. The enormous technological prospect of topological quantum computation provides new motivation for experimentally observing a topological state. Here, we explicitly work out a realistic experimental scheme to create and braid the Abelian topological excitations in the Kitaev model built on a tunable robust system, a cold atom optical lattice. We also demonstrate how to detect the key feature of these excitations: their braiding statistics. Observation of this statistics would directly establish the existence of anyons, quantum particles that are neither fermions nor bosons. In addition to establishing topological matter, the experimental scheme we develop here can also be adapted to a non-Abelian topological state, supported by the same Kitaev model but in a different parameter regime, to eventually build topologically protected quantum gates.},
 bibtype = {article},
 author = {Zhang, C. and Scarola, V. W. and Tewari, S. and Das Sarma, S.},
 doi = {10.1073/pnas.0709075104},
 journal = {Proceedings of the National Academy of Sciences},
 number = {47}
}

Topological quantum states of matter, both Abelian and non-Abelian, are characterized by excitations whose wavefunctions undergo nontrivial statistical transformations as one excitation is moved (braided) around another. Topological quantum computation proposes to use the topological protection and the braiding statistics of a non-Abelian topological state to perform quantum computation. The enormous technological prospect of topological quantum computation provides new motivation for experimentally observing a topological state. Here, we explicitly work out a realistic experimental scheme to create and braid the Abelian topological excitations in the Kitaev model built on a tunable robust system, a cold atom optical lattice. We also demonstrate how to detect the key feature of these excitations: their braiding statistics. Observation of this statistics would directly establish the existence of anyons, quantum particles that are neither fermions nor bosons. In addition to establishing topological matter, the experimental scheme we develop here can also be adapted to a non-Abelian topological state, supported by the same Kitaev model but in a different parameter regime, to eventually build topologically protected quantum gates.

@article{
 title = {Emergence of artificial photons in an optical lattice},
 type = {article},
 year = {2006},
 pages = {200401},
 volume = {97},
 websites = {http://link.aps.org/doi/10.1103/PhysRevLett.97.200401},
 month = {11},
 day = {13},
 id = {8226e161-d49e-3fa0-9d97-3bd21d43a533},
 created = {2017-12-12T20:22:24.096Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.168Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Tewari2006},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We establish the theoretical feasibility of direct analog simulation of the compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We discuss the realizability of the topological Coulomb phase in extended Bose-Hubbard models in several optical lattice geometries. We predict the testable signatures of this emergent phase in noise correlation measurements, thus suggesting the possible emergence of artificial light in optical lattices.},
 bibtype = {article},
 author = {Tewari, Sumanta and Scarola, V. W. and Senthil, T. and Sarma, S. Das},
 doi = {10.1103/PhysRevLett.97.200401},
 journal = {Physical Review Letters},
 number = {20}
}

We establish the theoretical feasibility of direct analog simulation of the compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We discuss the realizability of the topological Coulomb phase in extended Bose-Hubbard models in several optical lattice geometries. We predict the testable signatures of this emergent phase in noise correlation measurements, thus suggesting the possible emergence of artificial light in optical lattices.

@article{
 title = {Cold-atom optical lattices as quantum analog simulators for aperiodic one-dimensional localization without disorder},
 type = {article},
 year = {2006},
 pages = {041609},
 volume = {73},
 websites = {https://link.aps.org/doi/10.1103/PhysRevA.73.041609},
 month = {4},
 day = {28},
 id = {25898f90-750e-33c9-969c-ffc6cddef4a0},
 created = {2017-12-12T20:22:24.966Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:02.847Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2006b},
 source_type = {JOUR},
 folder_uuids = {4dea6cad-aea6-4b8d-8508-752e5cfc5357},
 private_publication = {false},
 abstract = {Cold atom optical lattices allow for the study of quantum localization and mobility edges in a disorder-free environment. We predict the existence of an Anderson-like insulator with sharp mobility edges in a one-dimensional nearly-periodic optical lattice. We show that the mobility edge manifests itself as the early onset of pinning in center of mass dipole oscillations in the presence of a magnetic trap which should be observable in optical lattices.},
 bibtype = {article},
 author = {Scarola, V. W. and Das Sarma, S.},
 doi = {10.1103/PhysRevA.73.041609},
 journal = {Physical Review A},
 number = {4}
}

Cold atom optical lattices allow for the study of quantum localization and mobility edges in a disorder-free environment. We predict the existence of an Anderson-like insulator with sharp mobility edges in a one-dimensional nearly-periodic optical lattice. We show that the mobility edge manifests itself as the early onset of pinning in center of mass dipole oscillations in the presence of a magnetic trap which should be observable in optical lattices.

@article{
 title = {Searching for a supersolid in cold-atom optical lattices},
 type = {article},
 year = {2006},
 pages = {51601},
 volume = {73},
 websites = {http://dx.doi.org/10.1103/PhysRevA.73.051601},
 id = {6a434148-8251-334b-8737-da2554c6ef70},
 created = {2017-12-12T20:22:27.688Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:00.137Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2006a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We suggest a technique for the observation of a predicted supersolid phase in extended Bose-Hubbard models which are potentially realizable in cold-atom optical lattice systems. In particular, we discuss important subtleties arising from the existence of the trapping potential which lead to an externally imposed (as opposed to spontaneous) breaking of translational invariance. We show, by carefully including the trapping potential in our theoretical formalism, that noise correlations could prove instrumental in identifying the supersolid and density wave phases. We also find that the noise correlation peak width scales inversely with the relative size of trapped Mott domains.},
 bibtype = {article},
 author = {Scarola, V. W. and Demler, E. and Das Sarma, S.},
 doi = {10.1103/PhysRevA.73.051601},
 journal = {Physical Review A},
 number = {5}
}

We suggest a technique for the observation of a predicted supersolid phase in extended Bose-Hubbard models which are potentially realizable in cold-atom optical lattice systems. In particular, we discuss important subtleties arising from the existence of the trapping potential which lead to an externally imposed (as opposed to spontaneous) breaking of translational invariance. We show, by carefully including the trapping potential in our theoretical formalism, that noise correlations could prove instrumental in identifying the supersolid and density wave phases. We also find that the noise correlation peak width scales inversely with the relative size of trapped Mott domains.

@article{
 title = {Composite fermion theory of excitations in the fractional quantum Hall effect},
 type = {article},
 year = {2005},
 keywords = {A. Composite fermion,D. Fractional quantum Hall effects},
 pages = {602-609},
 volume = {135},
 websites = {http://dx.doi.org/10.1016/j.ssc.2005.04.033},
 id = {e99c9d9b-da81-39bd-a3f2-ee374b236e1d},
 created = {2017-12-12T20:22:22.149Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:04.668Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Jain2005},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Transport experiments are sensitive to charged 'quasiparticle' excitations of the fractional quantum Hall effect. Inelastic Raman scattering experiments have probed an amazing variety of other excitations: excitons, rotons, bi-rotons, trions, flavor altering excitons, spin waves, spin-flip excitons, and spin-flip rotons. This paper reviews the status of our theoretical understanding of these excitations. ?? 2005 Elsevier Ltd. All rights reserved.},
 bibtype = {article},
 author = {Jain, J. K. and Park, K. and Peterson, M. R. and Scarola, V. W.},
 doi = {10.1016/j.ssc.2005.04.033},
 journal = {Solid State Communications},
 number = {9-10}
}

Transport experiments are sensitive to charged 'quasiparticle' excitations of the fractional quantum Hall effect. Inelastic Raman scattering experiments have probed an amazing variety of other excitations: excitons, rotons, bi-rotons, trions, flavor altering excitons, spin waves, spin-flip excitons, and spin-flip rotons. This paper reviews the status of our theoretical understanding of these excitations. ?? 2005 Elsevier Ltd. All rights reserved.

@article{
 title = {Quantum phases of the extended bose-hubbard hamiltonian: Possibility of a supersolid state of cold atoms in optical lattices},
 type = {article},
 year = {2005},
 pages = {033003},
 volume = {95},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.95.033003},
 month = {7},
 day = {15},
 id = {a57d95b2-1814-337b-807b-99f3510f5a23},
 created = {2017-12-12T20:22:23.126Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:22:43.223Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2005},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Cold atom optical lattices typically simulate zero-range Hubbard models. We discuss the theoretical possibility of using excited states of optical lattices to generate extended range Hubbard models. We find that bosons confined to higher bands of optical lattices allow for a rich phase diagram, including the supersolid phase. Using Gutzwiller, mean-field theory we establish the parameter regime necessary to maintain metastable states generated by an extended Bose-Hubbard model.},
 bibtype = {article},
 author = {Scarola, V. W. and Das Sarma, S.},
 doi = {10.1103/PhysRevLett.95.033003},
 journal = {Physical Review Letters},
 number = {3}
}

Cold atom optical lattices typically simulate zero-range Hubbard models. We discuss the theoretical possibility of using excited states of optical lattices to generate extended range Hubbard models. We find that bosons confined to higher bands of optical lattices allow for a rich phase diagram, including the supersolid phase. Using Gutzwiller, mean-field theory we establish the parameter regime necessary to maintain metastable states generated by an extended Bose-Hubbard model.

@article{
 title = {Exchange gate in solid-state spin-quantum computation: The applicability of the Heisenberg model},
 type = {article},
 year = {2005},
 pages = {32340},
 volume = {71},
 websites = {http://dx.doi.org/10.1103/PhysRevA.71.032340},
 id = {ccc7b866-55c3-38c6-b20b-b63d825b032b},
 created = {2017-12-12T20:22:25.342Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:00.993Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2005a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Solid-state quantum-computing proposals rely on adiabatic operations of the exchange gate among localized spins in nanostructures. We study corrections to the Heisenberg interaction between lateral semiconductor quantum dots in an external magnetic field. Using exact diagonalization we obtain the regime of validity of the adiabatic approximation. We also find qualitative corrections to the Heisenberg model at high magnetic fields and in looped arrays of spins. Looped geometries of localized spins generate flux-dependent multispin terms which go beyond the basic Heisenberg model.},
 bibtype = {article},
 author = {Scarola, V. W. and Sarma, S. Das},
 doi = {10.1103/PhysRevA.71.032340},
 journal = {Physical Review A},
 number = {3}
}

Solid-state quantum-computing proposals rely on adiabatic operations of the exchange gate among localized spins in nanostructures. We study corrections to the Heisenberg interaction between lateral semiconductor quantum dots in an external magnetic field. Using exact diagonalization we obtain the regime of validity of the adiabatic approximation. We also find qualitative corrections to the Heisenberg model at high magnetic fields and in looped arrays of spins. Looped geometries of localized spins generate flux-dependent multispin terms which go beyond the basic Heisenberg model.

@article{
 title = {Pseudo-spin quantum computation in semiconductor nanostructures},
 type = {article},
 year = {2005},
 pages = {177-177},
 volume = {7},
 websites = {https://iopscience.iop.org/article/10.1088/1367-2630/7/1/177},
 month = {8},
 day = {26},
 id = {b8ab68ba-73aa-38df-b339-2b1c10c121d1},
 created = {2020-06-19T15:33:17.726Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-08-28T20:09:42.096Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2005b},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We theoretically show that spontaneously interlayer-coherent bilayer\nquantum Hall droplets should allow robust and fault-tolerant pseudospin\nquantum computation in semiconductor nanostructures with voltage-tuned\nexternal gates providing qubit control and a quantum Ising Hamiltonian\nproviding qubit entanglement. Using a spin-boson model, we estimate\ndecoherence to be small ( 10-5).},
 bibtype = {article},
 author = {Scarola, V. W. and Park, K. and Sarma, S Das},
 doi = {10.1088/1367-2630/7/1/177},
 journal = {New Journal of Physics},
 number = {October}
}

We theoretically show that spontaneously interlayer-coherent bilayer\nquantum Hall droplets should allow robust and fault-tolerant pseudospin\nquantum computation in semiconductor nanostructures with voltage-tuned\nexternal gates providing qubit control and a quantum Ising Hamiltonian\nproviding qubit entanglement. Using a spin-boson model, we estimate\ndecoherence to be small ( 10-5).

@article{
 title = {Chirality in quantum computation with spin cluster qubits},
 type = {article},
 year = {2004},
 pages = {120503},
 volume = {93},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.93.120503},
 id = {cebe9b3b-5a25-3c3d-a11a-a5fb45056998},
 created = {2017-12-12T20:22:21.759Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:32.867Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2004},
 source_type = {JOUR},
 folder_uuids = {4dea6cad-aea6-4b8d-8508-752e5cfc5357},
 private_publication = {false},
 abstract = {We study corrections to the Heisenberg interaction between several lateral, single-electron quantum dots. We show, using exact diagonalization, that three-body chiral terms couple triangular configurations to external sources of flux rather strongly. The chiral corrections impact single-qubit encodings utilizing loops of three or more Heisenberg coupled quantum dots.},
 bibtype = {article},
 author = {Scarola, V. W. and Park, K. and Das Sarma, S.},
 doi = {10.1103/PhysRevLett.93.120503},
 journal = {Physical Review Letters},
 number = {12}
}

We study corrections to the Heisenberg interaction between several lateral, single-electron quantum dots. We show, using exact diagonalization, that three-body chiral terms couple triangular configurations to external sources of flux rather strongly. The chiral corrections impact single-qubit encodings utilizing loops of three or more Heisenberg coupled quantum dots.

@article{
 title = {Pseudospin Quantum Computation in Semiconductor Nanostructures},
 type = {article},
 year = {2003},
 pages = {167903},
 volume = {91},
 websites = {https://link.aps.org/doi/10.1103/PhysRevLett.91.167903},
 month = {10},
 day = {16},
 id = {1bc2ba66-1ea0-33ac-8921-03571aad16a2},
 created = {2017-11-17T02:52:42.886Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2020-06-19T23:15:01.721Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2003},
 private_publication = {false},
 abstract = {The pseudospin quantum computation in semiconductor nanostructures was discussed. It was shown that spontaneously interlayer-coherent bilayer quantum Hall droplets (BQHD) should allow robust and fault-tolerant pseudospin quantum computation in semiconductor nanostructures. The results showed that the Coulomb interaction offered a natural entangling mechanism, opening the possibility of large scale quantum computing using BQHD.},
 bibtype = {article},
 author = {Scarola, V. W. and Park, K. and Sarma, S. Das},
 doi = {10.1103/PhysRevLett.91.167903},
 journal = {Physical Review Letters},
 number = {16}
}

The pseudospin quantum computation in semiconductor nanostructures was discussed. It was shown that spontaneously interlayer-coherent bilayer quantum Hall droplets (BQHD) should allow robust and fault-tolerant pseudospin quantum computation in semiconductor nanostructures. The results showed that the Coulomb interaction offered a natural entangling mechanism, opening the possibility of large scale quantum computing using BQHD.

@article{
 title = {Even-Odd Effect in Spontaneously Coherent Bilayer Quantum Hall Droplets},
 type = {article},
 year = {2003},
 pages = {026804},
 volume = {91},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.91.026804},
 month = {7},
 day = {11},
 id = {123ee602-627d-3639-b7ad-a296a666a910},
 created = {2017-12-12T20:22:25.268Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2021-05-06T22:01:30.186Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Park2003},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Using exact diagonalization in the disk geometry we predict a novel\neven-odd effect in the Coulomb-blockade spectra of vertically coupled\ndouble quantum dots under an external magnetic field. The even-odd\neffect in the tunneling conductance is a direct manifestation of\nspontaneous interlayer phase coherence, and is similar to the even-odd\nresonance in the Cooper pair box problem in mesoscopic superconducting\ngrains. Coherent fluctuations in the number of Cooper pairs in superconductors\nare analogous to the fluctuations in the relative number difference\nbetween the two layers in quantum Hall droplets.},
 bibtype = {article},
 author = {Park, K and Scarola, V W and Das Sarma, S.},
 doi = {10.1103/PhysRevLett.91.026804},
 journal = {Physical Review Letters},
 number = {2}
}

Using exact diagonalization in the disk geometry we predict a novel\neven-odd effect in the Coulomb-blockade spectra of vertically coupled\ndouble quantum dots under an external magnetic field. The even-odd\neffect in the tunneling conductance is a direct manifestation of\nspontaneous interlayer phase coherence, and is similar to the even-odd\nresonance in the Cooper pair box problem in mesoscopic superconducting\ngrains. Coherent fluctuations in the number of Cooper pairs in superconductors\nare analogous to the fluctuations in the relative number difference\nbetween the two layers in quantum Hall droplets.

@article{
 title = {Excitation gaps of incompressible composite fermion states: Approach to the Fermi sea},
 type = {article},
 year = {2002},
 pages = {1553201-1553206},
 volume = {66},
 websites = {http://dx.doi.org/10.1103/PhysRevB.66.155320},
 id = {f8c7a424-328b-34a7-b8ce-0d5afdfb2990},
 created = {2017-12-12T20:22:22.820Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-05T00:16:40.673Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2002b},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Activation gaps are determined for fractional quantum Hall states\nwith up to seven filled Landau levels of composite fermions carrying\ntwo vortices, which correspond to electron filling factors of up\nto 7/15 along the sequence nu =n/(2n+1). Systems with as many as\n100 composite fermions are studied for this purpose. The relevance\nof the results to the issues of composite-fermion mass and the stability\nof fractional quantum Hall effect along the sequence n/(2n+1) is\ndiscussed.},
 bibtype = {article},
 author = {Scarola, V. W. and Lee, S. Y. and Jain, J. K.},
 doi = {10.1103/PhysRevB.66.155320},
 journal = {Physical Review B},
 number = {15}
}

Activation gaps are determined for fractional quantum Hall states\nwith up to seven filled Landau levels of composite fermions carrying\ntwo vortices, which correspond to electron filling factors of up\nto 7/15 along the sequence nu =n/(2n+1). Systems with as many as\n100 composite fermions are studied for this purpose. The relevance\nof the results to the issues of composite-fermion mass and the stability\nof fractional quantum Hall effect along the sequence n/(2n+1) is\ndiscussed.

@article{
 title = {Structures for interacting composite fermions: Stripes, bubbles, and fractional quantum Hall effect},
 type = {article},
 year = {2002},
 pages = {853361-8533613},
 volume = {66},
 websites = {http://dx.doi.org/10.1103/PhysRevB.66.085336},
 id = {315ef767-7809-3496-ad78-e6b6fc5fa790},
 created = {2017-12-12T20:22:23.962Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:01.964Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lee2002},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Much of the present day qualitative phenomenology of the fractional quantum Hall effect can be understood by neglecting the interactions between composite fermions altogether. For example the fractional quantum Hall effect at $\nu=n/(2pn\pm 1)$ corresponds to filled composite-fermion Landau levels,and the compressible state at $\nu=1/2p$ to the Fermi sea of composite fermions. Away from these filling factors, the residual interactions between composite fermions will determine the nature of the ground state. In this article, a model is constructed for the residual interaction between composite fermions, and various possible states are considered in a variational approach. Our study suggests formation of composite-fermion stripes, bubble crystals, as well as fractional quantum Hall states for appropriate situations.},
 bibtype = {article},
 author = {Lee, Seung Yeop and Scarola, Vito W. and Jain, J. K.},
 doi = {10.1103/PhysRevB.66.085336},
 journal = {Physical Review B},
 number = {8}
}

Much of the present day qualitative phenomenology of the fractional quantum Hall effect can be understood by neglecting the interactions between composite fermions altogether. For example the fractional quantum Hall effect at $\nu=n/(2pn\pm 1)$ corresponds to filled composite-fermion Landau levels,and the compressible state at $\nu=1/2p$ to the Fermi sea of composite fermions. Away from these filling factors, the residual interactions between composite fermions will determine the nature of the ground state. In this article, a model is constructed for the residual interaction between composite fermions, and various possible states are considered in a variational approach. Our study suggests formation of composite-fermion stripes, bubble crystals, as well as fractional quantum Hall states for appropriate situations.

@article{
 title = {Phonon drag effect in single-walled carbon nanotubes},
 type = {article},
 year = {2002},
 pages = {2054051-2054057},
 volume = {66},
 websites = {http://dx.doi.org/10.1103/PhysRevB.66.205405},
 id = {286d5947-2565-3c25-bb09-9832c964f6b0},
 created = {2017-12-12T20:22:24.942Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:01:55.867Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2002a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {A variational solution of the coupled electron-phonon Boltzmann equations is used to calculate the phonon drag contribution to the thermopower in a 1-D system. A simple formula is derived for the temperature dependence of the phonon drag in metallic, single-walled carbon nanotubes. Scattering between different electronic bands yields nonzero values for the phonon drag as the Fermi level varies.},
 bibtype = {article},
 author = {Scarola, V. W. and Mahan, G. D.},
 doi = {10.1103/PhysRevB.66.205405},
 journal = {Physical Review B},
 number = {20}
}

A variational solution of the coupled electron-phonon Boltzmann equations is used to calculate the phonon drag contribution to the thermopower in a 1-D system. A simple formula is derived for the temperature dependence of the phonon drag in metallic, single-walled carbon nanotubes. Scattering between different electronic bands yields nonzero values for the phonon drag as the Fermi level varies.

@article{
 title = {Possible pairing-induced even-denominator fractional quantum Hall effect in the lowest landau level},
 type = {article},
 year = {2002},
 pages = {2168041-2168044},
 volume = {88},
 websites = {http://dx.doi.org/10.1103/PhysRevLett.88.216804},
 month = {5},
 day = {14},
 id = {7499a3b8-0069-3fcd-9a8b-609a7557198f},
 created = {2017-12-12T20:22:26.214Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2019-12-04T20:11:33.051Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2002c},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We report on our theoretical investigations that point to the possibility\nof a fractional quantum Hall effect with partial spin polarization\nat v = 3/8. The physics of the incompressible state proposed here\ninvolves p-wave pairing of composite fermions in the spin reversed\nsector. The temperature and magnetic field regimes for the realization\nof this state are estimated.},
 bibtype = {article},
 author = {Scarola, V. W. and Jain, J. K. and Rezayi, E. H.},
 doi = {10.1103/PhysRevLett.88.216804},
 journal = {Physical Review Letters},
 number = {21}
}

We report on our theoretical investigations that point to the possibility\nof a fractional quantum Hall effect with partial spin polarization\nat v = 3/8. The physics of the incompressible state proposed here\ninvolves p-wave pairing of composite fermions in the spin reversed\nsector. The temperature and magnetic field regimes for the realization\nof this state are estimated.

@article{
 title = {Possible new phases of composite fermions.},
 type = {article},
 year = {2002},
 pages = {2946-2951},
 volume = {16},
 websites = {http://dx.doi.org/10.1142/S0217979202013262},
 id = {24478290-8a23-3e52-bb73-b81858652857},
 created = {2017-12-12T20:22:26.892Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:22:37.930Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2002},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {When the effective filling factor of composite fermions is an integer,\nthe residual interaction between them can often be neglected because\nthe ground state of the non-interacting model is unique and incompressible.\nHowever, at non-integer composite fermion (CF) filling factors the\nground state of composite fermions is enormously degenerate if the\ninteraction between them is neglected, and consideration of the\ninter composite fermion interaction is necessary for determining\nthe true ground state. In this article, we summarize certain results\nregarding what new states the inter composite fermion interaction\ncan possibly produce. },
 bibtype = {article},
 author = {Scarola, V W and Lee, S Y and Jain, J K},
 journal = {International Journal of Modern Physics B},
 number = {20-22}
}

When the effective filling factor of composite fermions is an integer,\nthe residual interaction between them can often be neglected because\nthe ground state of the non-interacting model is unique and incompressible.\nHowever, at non-integer composite fermion (CF) filling factors the\nground state of composite fermions is enormously degenerate if the\ninteraction between them is neglected, and consideration of the\ninter composite fermion interaction is necessary for determining\nthe true ground state. In this article, we summarize certain results\nregarding what new states the inter composite fermion interaction\ncan possibly produce.

@article{
 title = {Stripe Formation in the Fractional Quantum Hall Regime},
 type = {article},
 year = {2001},
 pages = {256803},
 volume = {87},
 websites = {https://link.aps.org/doi/10.1103/PhysRevLett.87.256803},
 month = {11},
 day = {29},
 id = {b3da7102-6be0-3bc2-a556-5d11c9813ef3},
 created = {2017-12-12T20:22:23.397Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:22:46.362Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Lee2001},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Even-denominator fractions of the form ν = (2n + 1)/(4n + 4) are addressed to account for Landau Level (LL) fillings. The finer structure the weak interaction could produce is shown. The observations apply to ν = (2n + 3)/(4n + 4) due to particle hole symmetry in the Lowest LL.},
 bibtype = {article},
 author = {Lee, Seung-Yeop and Scarola, Vito W. and Jain, J. K.},
 doi = {10.1103/PhysRevLett.87.256803},
 journal = {Physical Review Letters},
 number = {25}
}

Even-denominator fractions of the form ν = (2n + 1)/(4n + 4) are addressed to account for Landau Level (LL) fillings. The finer structure the weak interaction could produce is shown. The observations apply to ν = (2n + 3)/(4n + 4) due to particle hole symmetry in the Lowest LL.

@article{
 title = {Phase diagram of bilayer composite fermion states},
 type = {article},
 year = {2001},
 pages = {853131-8531310},
 volume = {64},
 websites = {http://dx.doi.org/10.1103/PhysRevB.64.085313},
 month = {8},
 day = {7},
 id = {515f9b24-1b57-3934-9f19-52f1f694a698},
 created = {2017-12-12T20:22:25.625Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-07-05T22:02:02.130Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2001},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {We construct a class of composite fermion states for bilayer electron systems in a strong transverse magnetic field, and determine quantitatively the phase diagram as a function of the layer separation, layer thickness, and electron density, while neglecting interlayer tunneling. We find, in general, that there are several transitions, and that the incompressible phases are separated by compressible ones. The paired states of composite fermions, described by Pfaffian wave functions, are also considered.},
 bibtype = {article},
 author = {Scarola, V. W. and Jain, J. K.},
 doi = {10.1103/PhysRevB.64.085313},
 journal = {Physical Review B},
 number = {8}
}

We construct a class of composite fermion states for bilayer electron systems in a strong transverse magnetic field, and determine quantitatively the phase diagram as a function of the layer separation, layer thickness, and electron density, while neglecting interlayer tunneling. We find, in general, that there are several transitions, and that the incompressible phases are separated by compressible ones. The paired states of composite fermions, described by Pfaffian wave functions, are also considered.

@article{
 title = {Interacting composite fermions},
 type = {article},
 year = {2001},
 pages = {117-122},
 volume = {117},
 websites = {http://dx.doi.org/10.1016/S0038-1098(00)00440-3},
 id = {4eecb665-3fbb-3fba-9e95-35f14876ca73},
 created = {2017-12-12T20:22:27.843Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2017-12-12T20:23:37.056Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Jain2001},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {Even though much of the dramatic physics of two-dimensional electrons in a high magnetic field is explicable in terms of weakly interacting composite fermions (CFs), the inter-CF interaction is responsible for many interesting, non-trivial phenomena. Here, we discuss four examples. (i) At small filling factors, a softening of the roton mode destroys the fractional Hall effect, giving way to the Wigner crystal. (ii) In higher Landau levels, the fractional Hall effect is destroyed due to a collapse of the energy of the neutral exciton. (iii) At ν = 5/2, the Fermi sea of CFs is unstable to Cooper pairing of CFs, thereby opening up a gap and producing a fractional Hall effect. (iv) Prior to the transition into the Wigner crystal, the CF liquid exhibits the Bloch instability into a magnetically ordered, spontaneously broken symmetry phase.},
 bibtype = {article},
 author = {Jain, J. K. and Kamilla, R. K. and Park, K. and Scarola, V. W.},
 doi = {10.1016/S0038-1098(00)00440-3},
 journal = {Solid State Communications},
 number = {3}
}

Even though much of the dramatic physics of two-dimensional electrons in a high magnetic field is explicable in terms of weakly interacting composite fermions (CFs), the inter-CF interaction is responsible for many interesting, non-trivial phenomena. Here, we discuss four examples. (i) At small filling factors, a softening of the roton mode destroys the fractional Hall effect, giving way to the Wigner crystal. (ii) In higher Landau levels, the fractional Hall effect is destroyed due to a collapse of the energy of the neutral exciton. (iii) At ν = 5/2, the Fermi sea of CFs is unstable to Cooper pairing of CFs, thereby opening up a gap and producing a fractional Hall effect. (iv) Prior to the transition into the Wigner crystal, the CF liquid exhibits the Bloch instability into a magnetically ordered, spontaneously broken symmetry phase.

@article{
 title = {Excitonic collapse of higher Landau level fractional quantum Hall effect},
 type = {article},
 year = {2000},
 pages = {R16259-R16262},
 volume = {62},
 websites = {http://dx.doi.org/10.1103/PhysRevB.62.R16259},
 id = {08facea6-ab15-340e-ab07-40faf552ed5e},
 created = {2017-12-12T20:22:24.921Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-05T00:17:06.722Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2000b},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {The scarcity of the fractional quantum Hall effect in higher Landau levels is a most intriguing fact when contrasted with its great abundance in the lowest Landau level. This paper shows that a suppression of the hard core repulsion in going from the lowest Landau level to higher Landau levels leads to a collapse of the energy of the neutral excitation, destabilizing all fractional states in the third and higher Landau levels, and almost all in the second Landau level. The remaining fractions are in agreement with those observed experimentally.},
 bibtype = {article},
 author = {Scarola, V. W. and Park, Kwon and Jain, J. K.},
 doi = {10.1103/PhysRevB.62.R16259},
 journal = {Physical Review B},
 number = {24}
}

The scarcity of the fractional quantum Hall effect in higher Landau levels is a most intriguing fact when contrasted with its great abundance in the lowest Landau level. This paper shows that a suppression of the hard core repulsion in going from the lowest Landau level to higher Landau levels leads to a collapse of the energy of the neutral excitation, destabilizing all fractional states in the third and higher Landau levels, and almost all in the second Landau level. The remaining fractions are in agreement with those observed experimentally.

@article{
 title = {Rotons of composite fermions: Comparison between theory and experiment},
 type = {article},
 year = {2000},
 keywords = {Composite fermions,[Project] TCI,fQHE},
 pages = {13064-13072},
 volume = {61},
 websites = {http://link.aps.org/doi/10.1103/PhysRevB.61.13064},
 id = {e2870ad9-14bd-350e-94ad-14b13762ede6},
 created = {2017-12-12T20:22:25.077Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-05T00:15:34.442Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2000},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {This paper reports results of our comprehensive theoretical study of the rotons of composite fermions. The calculated roton energies at Landau-level fillings of 1/3, 2/5, and 3/7 are in excellent agreement with the energies measured in inelastic light scattering and ballistic phonon absorption experiments.},
 bibtype = {article},
 author = {Scarola, Vito W and Park, Kwon and Jain, Jainendra K},
 doi = {10.1103/PhysRevB.61.13064},
 journal = {Physical Review B},
 number = {19}
}

This paper reports results of our comprehensive theoretical study of the rotons of composite fermions. The calculated roton energies at Landau-level fillings of 1/3, 2/5, and 3/7 are in excellent agreement with the energies measured in inelastic light scattering and ballistic phonon absorption experiments.

@article{
 title = {Cooper instability of composite fermions},
 type = {article},
 year = {2000},
 pages = {863-865},
 volume = {406},
 websites = {http://dx.doi.org/10.1038/35022524},
 id = {9747fe83-c3bc-3134-9dbf-e06eb31aa988},
 created = {2017-12-12T20:22:25.695Z},
 file_attached = {true},
 profile_id = {004c1ae0-7ed4-35f3-b39b-28665b4ab9a2},
 last_modified = {2022-08-05T17:29:12.302Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 citation_key = {Scarola2000a},
 source_type = {JOUR},
 private_publication = {false},
 abstract = {When confined to two dimensions and exposed to a strong magnetic field, electrons screen the Coulomb interaction in a topological fashion; they capture and even number of quantum vortices and transform into particl es called `composite fermions'. The fractional quantum Hall effect occurs in such a system when the ratio (or `filling factor', $\nu$) of the number of electrons and the degeneracy of their spin-split energy states (the Landau levels) takes on particular values. The Landau level filling $\nu=1/2$ corresponds to a metallic state in which the composite fermions form a gapless Fermi sea. But for $\nu=5/2$, a fractional quantum Hall effect is observed instead; this unexpected result is the subject of considerable debate and controversy. Here we investigate the difference between these states by considering the theoretical problem of two composite fermions on top of a fully polarized Fermi sea of composite fermions. We find that they undergo Cooper pairing to form a p-wave bound state at $\nu=5/2$, but not at $\nu=1/2$. In effect, the repulsive Coulomb interaction between electrons is overscr eened in the $\nu=5/2$ state by the formation of composite fermions, resulting in a weak, attractive interaction.},
 bibtype = {article},
 author = {Scarola, Vito W. and Park, Kwon and Jain, J. K.},
 doi = {10.1038/35022524},
 journal = {Nature},
 number = {6798}
}

When confined to two dimensions and exposed to a strong magnetic field, electrons screen the Coulomb interaction in a topological fashion; they capture and even number of quantum vortices and transform into particl es called `composite fermions'. The fractional quantum Hall effect occurs in such a system when the ratio (or `filling factor', $\nu$) of the number of electrons and the degeneracy of their spin-split energy states (the Landau levels) takes on particular values. The Landau level filling $\nu=1/2$ corresponds to a metallic state in which the composite fermions form a gapless Fermi sea. But for $\nu=5/2$, a fractional quantum Hall effect is observed instead; this unexpected result is the subject of considerable debate and controversy. Here we investigate the difference between these states by considering the theoretical problem of two composite fermions on top of a fully polarized Fermi sea of composite fermions. We find that they undergo Cooper pairing to form a p-wave bound state at $\nu=5/2$, but not at $\nu=1/2$. In effect, the repulsive Coulomb interaction between electrons is overscr eened in the $\nu=5/2$ state by the formation of composite fermions, resulting in a weak, attractive interaction.